1 The Supreme Court has summarized the filed-rate doctrine as "bar[ring] a regulated seller of

natural gas from collecting a rate other than the one filed with the Commission and prevent[ing]

the Commission itself from imposing a rate increase for gas already sold." Arkansas Louisiana

Gas Co. v. Hall, 453 U.S. 571, 578, 101 S.Ct. 2925, 2931, 69 L.Ed.2d 856 (1981) (" Arkla "); cf.

Montana-Dakota Utils. Co. v. Northw estern Pub. Serv. Co., 341 U.S. 246, 251, 71 S.Ct. 692,

695, 95 L.Ed. 912 (1951) (ruling that a pipeline "can claim no rate as a legal right that is other

than the filed rate, whether fixed or merely accepted by the Commission, and not even a court can

authorize commerce in the commodity on other terms").

Some courts have tried to parse the doctrine by implying that it merely provides

that a natural gas company may legally impose no rate other than the one filed with the

Commission and that a "corollary" of the doctrine—the rule against retroactive

ratemaking—prevents the Commission from permitting a pipeline from raising rates on gas

already sold. See, e.g., Transcontinental Gas Pipe Line Corp. v. FERC, 54 F.3d 893, 898

(D.C.Cir.1995) (" Transco "); Public Utils. Comm'n of Cal. v. FERC, 988 F.2d 154, 163-

64 (D.C.Cir.1993) (" CPUC "); Associated Gas Distribs. v. FERC, 898 F.2d 809, 810

(D.C.Cir.1990) (per curiam) (Williams, J., concurring). However, these same courts have

conceded that the doctrine and its corollary serve the same purposes and often overlap.

See, e.g., CPUC, 988 F.2d at 164 n. 2; Associated Gas Distribs., 898 F.2d at 810

(Williams, J., concurring).

We decline to follow this practice. Not only is it unnecessarily confusing and

unwieldy, but it has not been adopted by the Supreme Court or the Commission. Indeed,

1 United States Court of Appeals,

Fifth Circuit.

Nos. 95-60553, 95-60636.

TEXAS EASTERN TRANSMISSION CORPORATION, Petitioner,

v.

FEDERAL ENERGY REGULATORY COMMISSION, Respondent.

Dec. 30, 1996.

Petition for Review of Orders of the Federal Energy Regulatory Commission.

Before HIGGINBOTHAM, BARKSDALE and EMILIO M. GARZA, Circuit Judges.

EMILIO M. GARZA, Circuit Judge:

Petitioner Texas Eastern Transmission Corporati on ("TETCO") appeals a decision by

respondent Federal Energy Regulatory Commission ("FERC") to apply the filed-rate doctrine to

preclude TETCO from retroactively assessing certain customers (the "customers") rates based on a

different rate methodology than it previously imposed. 1 Some of these customers have intervenedin the orders on review here, the Commission consistently uses the filed-rate doctrine in a

way that suggests the doctrine subsumes the rule against retroactive ratemaking.

2 The intervenors in this case include Public Service Electric and Gas Co. ("PSE & G"), New

Jersey Natural Gas Co. ("New Jersey"), Bristol and Warren Gas Co. ("B & W"), Colonial Gas

Co. ("Colonial"), Bay State Gas Co., Boston Gas Co., Commonwealth Gas Co., Fall River Gas

Co., Northern Utilities, Inc., and The Providence Gas Co. According to TETCO, only four of the

intervenors—PSE & G, New Jersey, B & W, and Colonial—are customers who would be

affected by this case.

2 in this lawsuit to support FERC on appeal. 2 We affirm.

I

Given the complexity of this case and the nature of the legal issues it raises, we must set forth

its tangled factual and procedural history at length.

In October 1988, TETCO applied for a certificate of public convenience and necessity under

§ 7 of the Natural Gas Act ("the NGA"). TETCO sought authority to construct facilities and provide

services dealing with the Associated PennEast Customer Group ("APEC") I and III proj ects,

including facilities to provide service under Rate Schedules FTS-4 and FTS-5. At the same t ime,

three other companies, including Transcontinental Gas Pipe Line Corp. ("Transco"), sought similar

authority.

TETCO had previously entered into various service agreements with its customers. These

agreements require the customers to pay TETCO "applicable prices established und er [TETCO's]

Rate Schedule FTS-4 [and FTS-5] as f iled with [FERC], and as same may hereafter be legally

amended or superseded." Apparently, Transco had also entered into similar agreements with certain

of its customers.

In their respective applications for a certificate, TETCO and Transco requested, among other

things, permission to use a "straight fixed variabl e" ("SFV") rate desi gn m ethod. Under SFV, a

pipeline typically recovers all of its fixed costs through a demand charge and all of its variable costs

through a commodity charge. Pipeline customers pay the demand charge each month for the right3 In this case, TETCO sought (and the customers agreed to) SFV with a commodity charge of

zero. Thus, the form of SFV at issue here is really a 100 percent demand rate design, that is, one

in which TETCO would recover both its fixed and commodity costs through demand charges.

For convenience, we will refer to this design as "SFV."

4 Philadelphia Electric Company, a customer, sought a rehearing on a separate matter. The

Commission denied the request.

3 to receive service and the commodity charge for their actual use of the service. 3 In contrast, TETCO

and Transco had previously been using a modified fixed variable ("MFV") rate design fo r t heir

services and facilities. Under MFV, a pipeline can recover its fixed and variable costs only through

commodity charges. In other words, MFV (unlike SFV) only permits a pipeline to recover its fixed

costs if its customers actually use the service.

On June 7, 1989, the Commission granted TETC O's application in part. The Commission

accorded it certificate authority to provide the FTS-4 and FTS-5 service, however it refused to allow

TETCO to use the SFV method. Rather, it only authorized TETCO to use MFV. The Commission,

though, was careful to state that it did not necessarily believe that MFV "should or must apply" to

TETCO's application for authority to provide "additional services and facilit ies for any extended

period of time." 47 F.E.R.C. ¶ 61,341 (1989). Instead, its decision t o opt for MFV "reflects our

conclusion that it is appropriate as an init ial matte r t o have consistency between the current rate

design utilized on those pipelines and that adopted here for the additional services and facilities...."

Id.

TETCO did not seek rehearing of this decision. However, Transco, which received a similar

ruling to TETCO in t he proceeding, did. 4 On June 21, 1991, the Commission granted Transco's

request for a rehearing in part. The Commission stated that its decision to grant t he request was

"based upon our determination that agreements among the pipelines and their customers regarding

rate design should be given significant weight." 55 F.E.R.C. ¶ 61,477 (1991). It further noted that

there was no evidence that Transco's customers had agreed to SFV "for other tha n legit imate

commercial reasons." Id. While the Commission's order did not specify an effective date for SFV,

Transco filed tariff sheets to make the design retroactively effective as of the date of initial service5 Algonquin Gas Transmission Co., one of the other parties subject to the June 1989 certificate

order, made a similar request for rehearing.

4 for its new facilities and services. The Commission accepted the sheets.

After the Commission's decision in favor of Transco, TETCO requested a rehearing of the

June 1991 order, arguing that the Commission should h ave permi tted TETCO to use the SFV

method, just as it did Transco. 5

On March 5, 1992 , the Commission concluded that not granting TETCO relief in its June

1991 order was perfectly proper, but that it would nevertheless reconsider its June 1989 certificate

order and authorize TETCO to use SFV. The Commission noted that, just like Transco, TETCO and

its customers had agreed to SFV, and there was n o evidence to suggest that the custom ers had

consented to it for other than legitimate commercial reasons. Again, the order did not specify an

effective date. In April 1992, TETCO filed tariff sheets, requesting that SFV be retroactively

effective as of November 15, 1989, the date of TETCO's initial APEC I service.

Several weeks later, the customers filed a request for "clarification" of the March 1992 order

and a protest of the April tariff-sheet filing. The customers asked that the Commission clarify that

the March 1992 order was not retroactive—which they claimed would be violation of the filed-rate

doctrine—and that it only permit TETCO's filed tariff sheets to be effective prospectively.

In an order issued June 24, 1993, the Commission rejected the customers' argument that a

retroactive change of rates in this matter would violate the filed-rate doctrine. This is because, the

Commission explained, "TETCO proposed the use of the SFV rate design methodology in its original

certificate application, reflecting the APEC customers' consent to the use of the SFV method." 63

F.E.R.C. ¶ 61,327 (1993). Still, the Commission accepted the customers' contention that TETCO's

tariff sheets should not be retroactively effective on three grounds. First, the Commission found that

"to accept the SFV r at es retroactively in the instant filing effective November 15, 1989 would be

inconsistent with the Commission's decisions in the Transco Sout hern Expansion proceeding, in which

the Commission found that it would be inequitable to the Southern Expansion customers to place the6 The Transco Southern Expansion proceeding differs from the APEC I and III proceeding

involving Transco. In the Southern Expansion proceeding, which the Commission found

"analogous to this case," the Commission initially rejected Transco's proposed SFV rate design

and, in a May 14, 1990 order, required Transco to use SFV. Transco then requested a rehearing.

On July 5, 1991, the Commission reconsidered its May 1990 order and permitted Transco to use

SFV. Transco then filed tariff sheets implementing SFV effective as of November 1, 1990, the

initial date of service, and these were accepted by the Commission. After Transco's customers

filed a protest, the Commission changed the effective date for SFV to July 5, 1991, the date the

Commission, on rehearing, authorized Transco to use SFV. In doing so, the Commission rejected

Transco's arguments that its customers had had notice that SFV rates might be retroactively

applied to them. The parties filed more requests for rehearing on the effective date. The

Commission then moved the effective date up further, to November 1, 1991, exactly a year after

the initial date of service. The Commission did so to avoid prejudicing any seasonal customer.

Transco appealed to the D.C. Circuit. In its decision, that court began by noting

that the Commission's stated rationale in refusing to adopt the 1990 effective date was that

such an early date "would defeat the legitimate expectations of those customers ... that

limited their use of the service because of the MFV rates on file between the

commencement of service and July 5, 1991." Transco, 54 F.3d at 899. The court rejected

this explanation, however, pointing out that the Commission never discussed what

legitimated these expectations and "never even considered the expectations of customers

that used the service heavily, even though they may have done so in reliance on an

expectation that ultimately FERC would—as it did—honor the agreement between

Transco and its customers." Id. Indeed, the court seemed to conclude that a customer

could not reasonably have expected that the Commission's resolution of the SFV/MFV

issue would only apply prospectively. Examining two relevant FERC decisions— Black

Marlin, 48 F.E.R.C. ¶ 61,024 (1989) and KN Energy, Inc., 50 F.E.R.C. ¶ 61,290

(1990)—the court ruled that these decisions "seemingly" represented a norm that

where service starts under § 7 before final determination of the rates, the rate

finally determined will be applied retroactively to the start of service. That norm

cuts powerfully for finding the rates effective as of November 1, 1990, and against

any expectations to the contrary. The norm makes a good deal of sense, as it

means that the "right rate", i.e., whatever rate the Commission lawfully determines

to be right, is applied throughout the period despite the Commission's initial

uncertainty and delay. The expectations of those who act in anticipation of the

right rate are protected, and they would seem presumptively most deserving.

Id. Still, the court decided to remand because there might be some legitimate reason, not

yet articulated, for the Commission to apply MFV rather than SFV to the period from

November 1, 1990 to November 1, 1991.

On remand, the Commission found that November 1, 1990 was the most effective

date for SFV. The Commission based this decision on three grounds: (1) "traditionally

when service commences on newly certified NGA section 7 facilities before the

Commission makes a final determination on the initial rate, the subsequently determined

initial rate applies retroactively to the date service commenced," (2) Transco's request for

a rehearing of the Commission's decision to permit it only to impose MFV put the

customers on notice that "the MFV issue was still open and subject to change," and (3) the

5 revised SFV rates into effect retroactively, as o f the date of initial se 6 Second, the CommissionCommission's order authorizing MFV referred to a Commission policy statement which

indicated that "the Commission's policy toward the MFV rate design was in a state of flux

at that time and there was a possibility that the Commission would reconsider its decision

on rehearing," which put the customers on notice that they would assume some risk in

basing purchasing decisions on the MFV rate. 73 F.E.R.C. ¶ 61,077.

6 accepted the customers' statement that they had made purchasing decisions in reliance on the "filed,

approved and uncontested" MFV-based init ial rates. I d. Third, the Commission held that the equities

of the case weighed in favor of the customers because they were not aware that TETCO would seek

a change in rate design until about twenty months after the initial rates took effect.

TETCO then requested a rehearing. In an August 3, 1995, order, the Commission conceded

that "mistakes were made" in bot h t he March 1992 and June 1993 orders. 72 F.E.R.C. ¶ 61,152

(1995). The Commission reiterated its previous determination that TETCO may not impose SFV

rates retroactively, however it arrived at this conclusion through a different analysis than before. The

Commission noted that, unlike Transco, TETCO had failed to seek t imely rehearing of the June 1989

certificate order. Hence, that order became final and nonappealable as applied to TETCO. "Under

the filed rate doctrine," the Commission ruled, "final rates approved by the Commission cannot be

charged retroactively. Thus, the mere fact that TETCO did not seek rehearing of the original

certificate order dictated that a modification in the rate design for TETCO's init ial rates would have

to be implemented prospectively." Id. Citing Transco, 54 F.3d 893, as authority, the Commission

stated that "where no t imely request for rehearing is filed, and thus no notice of a retroactive change

is provided, as in this case, the Commission cannot modify the rate design retroactively without

violating the filed rate doctrine." 72 F.E.R.C. ¶ 61,152.

TETCO then petitioned for a rehearing of the August 3 order. The Commission summarily

denied the request. 73 F.E.R.C. ¶ 61,039 (1995). Now, TETCO seeks review of the last three orders

issued by the Co mmissio n in this matter: (1) the June 24, 1993 order, published at 63 F.E.R.C. ¶

61,327; (2) the August 3, 1995 order, published at 72 F.E.R.C. ¶ 61,152; and (3) the October 5,7 TETCO is not permitted to seek review of the October 1995 order because it did not seek

rehearing of it. See 15 U.S.C. § 717r(a) ("No proceeding to review any order of the Commission

shall be brought by any person unless such person shall have made application to the Commission

for a rehearing thereon.").

8 This section provides that "[a]ny party to a proceeding under this chapter aggrieved by an

order issued by the Commission in such proceeding may obtain a review of such order in the court

of appeals of the United States for any circuit wherein the natural-gas company to which the order

relates is located or has its principal place of business...." Texas Eastern is based in this circuit.

9 In certain circumstances, parties may request leave from the court to adduce additional

evidence. 15 U.S.C. § 717r(b). None has done so here.

7 1995 order, published at 73 F.E.R.C. ¶ 61,039. 7

II

We have jurisdiction over this case under 15 U.S.C. § 717r(b)

. 8 While we may affirm,

mo dify, or set a side in whole or part any Commission order upon which an aggrieved party has

sought review, id., we must uphold FERC's orders unless they are "arbitrary, capricious, an abuse of

discretion, or otherwise not in accordance with law." 5 U.S.C. § 706(2)(A). "The findi ng of the

Commission as to the facts, if supported by substantial evidence, shall be conclusive." 9 15 U.S.C. §

717r(b); s ee also 5 U.S.C. § 706(2)(E) (stating that a court shall set aside agency findings found to

be unsupported by substantial evidence). Moreover, when "Congress has directly spoken to the

precise question at issue," a reviewing court must respect the legislators' decision; where a statute

is "silent or ambiguous," though, the court must accept any reasonable interpretation by the agency

to which Congress has entrusted the statute' s administrati on. C hevron U.S.A., Inc. v. Natural

Resources Defense Council, Inc., 467 U.S. 837, 842, 104 S.Ct. 2778, 2781, 81 L.Ed.2d 694 (1984).

On appeal, TETCO alleges a number of errors, which can be grouped in three categories.

First, TETCO argues that the Commission erred by applying the filed-rate doctrine. It contends that

this doctrine cannot be applied in a proceeding to set certificate r at es under § 7 of the NGA.

Alternatively, it avers that, even if the doctrine could apply in a § 7 proceeding, it did not apply in this

one because the MFV-based init ial rates permitted by the June 1989 order were provisional and the

customers had adequate notice that the Commission might permit SFV-based init ial rates. Second,8

TETCO claims that the Commission erred in finding in the August 1995 order that its decision would

not change the parties' financial positions. Third, it maintains that the Commission erred in its June

1993 order by entertaining the customers' "Request for Clarification" of the March 1992 order, and

erred in both its June 1993 and August 1995 orders by effectively negating the March 1992 order.

III

A

Section 7 of the NGA requires pipelines to obtain a certificate of public conve nience and

necessity from the Commission for, among other things, the construction and extension of natural gas

facilities. It also confers on the Commission the power to "attach to the issuance of the certificate

and to the exercise of the rights granted thereunder such reasonable terms and conditions as the public

convenience and necessit y may require." 15 U.S.C. § 717f(e). Sections 4 and 5 of the NGA

generally govern rates and charges. Section 4 of the NGA provides that natural gas rates be just and

reasonable, that natural gas companies file with the Commission schedules showing their ra tes f or

transporting or selling natural gas, that no natural ga s co mpany can change its rates without first

giving the Commission and the public thirty days' notice, and that the Commission may hold hearings

on the lawfulness of the rates in any new schedule filed. Section 5 allows the Commission, after a

hearing, to determine that a rate is unjust, unreasonable, unduly discriminatory, or preferential and

then to calculate a just and reasonable rate. The section also provides that the Commission may not

increase a rate in a schedule on file with it, unless this increase accords with a new schedule filed by

the affected natural gas company, but may order a decrease where "existing rates are unjust, unduly

discriminatory, preferential, otherwise unlawful, or are not the lowest reasonable rates." 15 U.S.C.

§ 717d(a).

TETCO acknowledges that the filed-rate doctrine has been uniformly applied to proceedings

under §§ 4 and 5 of the NGA, but asserts that it "cannot" be applied to a proceeding under § 7, such

as this one. In support of this claim, TETCO offers a convoluted argument based on what it claims

is industry practice. TETCO asserts that, when pipelines enter into agreements with their customers9

about rates before proceeding under § 4 or § 7, agreements about proposed § 4 rate change § 7 init ial

rates. Because there is more need for the filed-rate doctrine to protect customers against

unanticipated rate changes than unexpected init ial r at es, TETCO maintains, the filed-rate doctrine

only applies in § 4 (or § 5) proceedings.

This contention is incorrect for several reasons. First, the fact that the filed-rate doctrine may

be less needed to ensure adequate notice in § 7 proceedings than in § 4 ones does not mean that it

is never needed in § 7 proceedings. If customers truly have sufficient notice of initial rates through,

say, preexisting agreements, then the doctrine wi ll no t apply. If they lack sufficient notice, the

doctrine will apply.

Second, TETCO erroneously assumes that t he only policy behind the filed-rate doctrine is

ensuring that pipeline customers receive advance notice of new rates. However, other rationales for

the doctrine exist. S ee Nantahala Power and Light Co. v. Thornburg, 476 U.S. 953, 965, 106 S.Ct.

2349, 2356, 90 L.Ed.2d 943 (1986) (suggesting that doctrine ensures that interstate rates filed with

FERC are given binding effect by state utility commissions in determining intrastate rates); Arkla,

453 U.S. at 582, 101 S.Ct. at 2933 (stating that purpose of doctrine is "granting the Commission an

opportuni ty in every case to judge the reasonableness of the rate"); c f. Maislin Indus., U.S., Inc. v.

Primary Steel, Inc., 497 U.S. 116, 126, 110 S.Ct. 2759, 2765-66, 111 L.Ed.2d 94 (1990) (noting that

under Interstate Commerce Act, doctrine helps prevent unjust discrimination). While the policy of

ensuring that customers have adequate notice may be less necessary in § 7 proceedings than § 4 ones,

these other purposes are furthered by the filed-rate doctrine regardless of whether init ial rates or rate

changes are involved.

Third, TETCO's argument finds no support in the case law. To our knowledge, no court has

refused to apply the filed-rate doctrine because the rates involved happened to be init ial ones, and at

least one court has used the doctrine in just such a circumstance. In Transco, which also involved

a § 7 proceeding and has very simila r fact s t o this case, the D.C. Circuit explicitly found that the

filed-rate doctrine did not appl y because the customers had adequate notice of the proposed rates10 There is also a rather peculiar case in this circuit involving a § 7 certificate and rate increases.

In Mobil Exploration and Producing North America, Inc. v. FERC, 881 F.2d 193 (5th Cir.1989),

we held that the Commission did not misapply the filed-rate doctrine by exercising its discretion

(1) to permit successors to gas-selling predecessors to collect from customers the rate in effect on

the date of transfer of the interest in the gas-producing property during the time period between

that date and the date they filed to succeed to the predecessors' § 7 certificate but (2) not to

permit the successors to keep the rate increases they collected during this time period. We did

not state whether this was a § 7 or a § 4 case. It is probably both.

11 The filed-rate doctrine is not overcome or waived. See Columbia Gas Transmission Corp. v.

FERC, 895 F.2d 791, 797 (D.C.Cir.) (" Columbia II "), cert. denied, 498 U.S. 907, 111 S.Ct. 279,

112 L.Ed.2d 233 (1990) ("[W]e have found no support for the Commission's contention that ... it

has the authority ... to waive the filed rate doctrine."). Either it applies or it does not.

10 from the outset, not

because the case involved initial rates rather than rate changes. 10

In any event, the text of the NGA provides little, if any, guidance on whether the filed-rate

doctrine applies in § 7 proceedings. The Commission has decided that it applies in t his case.

Following Chevron, we find that the Commission's decision to invoke the filed-rate doctrine in a §

7 proceeding is reasonable.

B

TETCO next argues that, even if the filed-rate doctrine does apply in a § 7 proceeding, the

Commission erred by employing it here. It claims that the filed-rate doctrine may be "overcome" or

"waived" by adequate notice to the customers that different rates may be charged. 11 In this case, it

suggests, the customers had adequate notice because they specifically consented to SFV in

agreements with TETCO prior to TETCO's § 7 filing an d because t he Commission's June 1989

certificate order raised the possibility that the Commission might permit such rates.

The customers' agreements with TETCO apparently obligated them to pay "applicable prices

established under [TETCO's] Rate Schedule FTS-4 [and FTS-5] as filed with [FERC], and as same

may be legally amended or superseded." While the Commission disputes on appeal that this language

bound the customers to SFV, we believe that it did, at least init ially. For instance, in the March 1992

order, the Commission itself found that the customers had "agreed to" the proposed SFV rate design,

52 F.E.R.C. ¶ 61,254, and in the June 1993 order, it determined that the customers "agreed to, and

supported" SFV "at the outset of the proceeding." 63 F.E.R.C. ¶ 61,327. Second, the customers12 While the fact that the Commission reconsidered and modified its earlier "final" order may

make it seem less final, the Commission remains procedurally free to do so. 15 U.S.C. § 717r(a)

provides that

[u]ntil the record in a proceeding shall have been filed in a court of appeals ... the

Commission may at any time, upon reasonable notice and in such manner as it shall

deem proper, modify or set aside, in whole or in part, any finding or order made or

issued by it under the provisions of this chapter.

In Tennessee Gas Pipeline Co. v. FERC, 871 F.2d 1099 (D.C.Cir.1989), for instance, the

court held that the Commission could modify an order in response to an untimely "Motion

for Clarification."

13 The court ruled that "none of the possible outcomes [in the case] involves the sort of

"retroactive ratemaking' that is forbidden under the rule against retroactive ratemaking, a

corollary of the filed rate doctrine. Transco's petition for rehearing of the initial MFV order put

customers on notice that the SFV methodology might ultimately prevail, and such notice "changes

what would be purely retroactive ratemaking into a functionally prospective process by placing

the relevant audience on notice at the outset that the rates being promulgated are provisional only

and subject to later revision.' " Transco, 54 F.3d at 898 (quoting CPUC, 988 F.2d at 164).

11 concede in their brief that they agreed to SFV "as originally proposed."

Although the customers' agreements put them on notice of the possibility that the Commission

might authorize SFV-based init ial rates, the Commission did not permit such rates. Rather, it decided

that TETCO should use MFV instead. TETCO then failed to seek a rehearing, so the Commission's

decision became final as to TETCO. Subsequently, the Commission unilaterally reconsidered its June

1989 order authorizing MFV and concluded that TETCO could use SFV. 12 Still later, it determined

that TETCO could not impose SFV retroactively. The Commission reaso ned t hat the June 1989

order imposing MFV was final, and that, "[u]nder the filed rate doctrine, final rates approved by the

Commission cannot be changed ret roactively . Thus, the mere fact that TETCO did not seek

rehearing of the original certificate order [imposi ng MFV] dictated that a modification in the rate

design for TETCO's init

ial rates would have to be implemented prospectively." 72 F.E.R.C. ¶ 61,152.

The Commission relied heavily on Tra nsco, 54 F.3d 893, which held that the filed-rate

doctrine did not bar moving back the effective date of SFV to the date of service. The Commission

asserted that the fact that Transco (unlike TETCO) sought t imely rehearing of the order imposing

MFV "appeared to be critical" to the court's ruling. 13 It stated that the court's "reasoning implies that12

where no t imely request for rehearing is filed, and thus no notice of a retroactive change is provided,

as in this case, the Commission cannot modify the rate design retroactively without violating the filed

rate doctrine." 72 F.E.R.C. at 61,767. The Commission also noted that this ho lding mooted its

March 5, 1992 order permitting TETCO to use SFV because the MFV rates to which the March 5

order pertained were only in effect until November 30, 1990.

In understanding the Commission's conclusion, it is important to grasp the scop e of the

filed-rate doctrine. This doctrine generally holds that "once a rate is in place with ostensibly full legal

effect and is not made provisional, it can then be changed only prospectively." C olumbia II, 895 F.2d

at 797. However, the doctrine normally does not apply where the parties enter into preexisting

agreements on proposed rates. Such agreements provide the requisite notice and "change[ ] what

would be purely retroactive ratemaking into a functionally prospective process by placing the relevant

audience on notice at the outset that the rates being promulgated are provisional only and subject to

later revision." Id.

Thus, the Commission's co nclusio n in its August 1995 order really has two parts. First, it

determined that the filed-rate doctrine applied here because the notice provided by the agreements

no longer mattered. The fact t hat the parties had earlier agreed to SFV-based initial rates was

irrelevant because the Commission determined that TE TCO co uld only impose MFV-based initial

rates and TETCO did not seek rehearing of the Commission's decision; the MFV-based initial rates

became final. Second, it found that the customers, faced with final MFV-based initial rates, could

not have reasonably anticipated that the Commission would later unilaterally authorize TETCO to

use SFV for the init

ial rates. Thus, the customers lacked adequate notice of the possi rates could not

be imposed except in violation of the filed-rate doctrine.

In reviewing the Commission's decision, we must recognize the unusual nature of this case.

Unlike any other we have found, it involves a situation where cus t omers init ially had notice of the

possibility of certain rates through preexisting agreements but then arguably "lost" this notice when

a final Commission order authorized different rates. None of the cases we have examined in which13

the court found adequate notice (such as those with agreements to higher rates) involves notice

broken by a final Commission order. S ee Transco, 54 F.3d at 898 (finding that, where pipeline and

customers entered into agreements in which SFV could be impose d but Co mmission granted

certificate rejecting SFV in favor of MFV, pipeline's request for rehearing of certificate put customers

on notice that SFV might ultimately prevail); G ulf States Utils., Co. v. FERC, 1 F.3d 288, 292 (5th

Cir.1993) (ruling that customer not only had actual notice of rate increases through various filings

by pipeline, but the proposed changes are provided for by an agreement between the parties); C PUC,

988 F.2d at 166 (stating that customers had adequate notice that the pipeline's certificate conditions

were subject to change through the pipeline's petition for rehearing on an exclusivity provision, its

judicial appeal of a sunset prov ision, and through Commission's record of granting take-or-pay

charges); C

onEd, 958 F.2d at 434-35 (noting that customers had adequate notice from the pipeline's

request for a retroactive effective date and Commission's record of granting such requests); H all v.

FERC, 691 F.2d 1184, 1192 (5th Cir.1982) (after timely appeal and lengthy related litigation in

FERC and federal court, reversing Commission because it wrongly applied filed-rate doctrine to bar

an increase in rates the parties had previously authorized in a contract), cert. denied, 464 U.S. 822,

104 S.Ct. 88, 78 L.Ed.2d 96 (1983); C ity of Piqua v. FERC, 610 F.2d 950, 954-55 (D.C.Cir.1979)

(affirming Commission's refusal to apply filed-rate doctrine under Federal Power Act since the rate

change was prospective from the date of the contract in which the parties agreed to this rate change).

Co nversely, in the cases we have seen involving inadequate notice, there has been no

preexisting agre ement t o a rate change and/or no adequate notice of a rate change from the

Commission. S ee Transwestern Pipeline Co. v. FERC, 897 F.2d 570, 579-81 (D.C.Cir.) (where

Commission did not apply filed-rate doctrine to bar pipeline's collection of certain balan ces from

customers because they had adequate notice, rejecting Commission's argument that preambl e to

regulations suggested policy of assuring pipelines' recovery of all purchased gas costs because such

"notice" was inadequate and rebuffing Commission's contention that two FERC decisions allowed

recovery of balances in similar circumstances because these decisions did not involve the pipeline's14

particular system), cert. denied, 498 U.S. 952, 111 S.Ct. 373, 112 L.Ed.2d 335 (1990); C olumbia

II, 895 F.2d at 797 (holding that, in the absence of adequate notice fr om t he Commission or any

preexisting agreements to rate change, the Commission was barred by t he filed-rate doctrine from

permitting a surcharge on gas already sold); C olumbia Gas Transmission Corp. v. FERC, 831 F.2d

1135, 1138 (D.C.Cir.1987) (" Columbia I ") (ruling that, where Commission issued order informing

gas producers that it intended to allow them to pass along certain costs to their "first purchasers,"

these first pu rchasers could not pass these costs along to "downstream purchasers" because the

downstream purchasers were not the "audience" for the order and thus lacked adequate notice);

Gillring Oil Co. v. FERC, 566 F.2d 1323 (5th Cir.) (in which, according to Hall, 691 F.2d at 1191,

the pipeline "sought a rate higher than that ever filed with the Commission or contemplated by the

rate schedule/contract. A purer example of an action for a retroactive rate increase would be difficult

to imagine."), cert. denied, 493 U.S. 823, 99 S.Ct. 91, 58 L.Ed.2d 115 (1978).

1

TETCO first argues that the MFV-rates were not final, but provisional. It relies on various

st at ements in the June 1989 certificate order suggesting that the Commission was not particularly

wedded to MFV and would revisit the SFV/MFV issue. The order noted, for instance, that

[w]e emphasize that our approval of the initial rates herein does not constitut e an

endorsement of any underlying rat e methodology, principle, or concept. In particular, we

recognize that we are requiring the use of MFV rate design in lieu of methods proposed by

Texas Eastern

... even though the [Commission's May 30, 1989 Policy Statement Providing

Guidan ce With Respect to The Designing of Rates ] indicated that, "[t]he Commission is

concerned that MFV may be outdated in light of the significant changes in the nature of the

gas pipeline industry...."

47 F.E.R.C. ¶ 61,341. It also stated that

[o]ur decision here to require MFV reflects our conclusion that it is appropriate as an init ial

matter to have consistency between the current rate design utilized on those pipelines and that

adopted here for the additional services and facilit ies, pending subsequent application of the

policy statement to those pipelines, rather than any conclusion that the MFV for some reason

should or must apply separately to these additiona l services and facilities for any extended

period of time. Additionally, when the rates of these pipeline companies are next reviewed

i n a section 4 or 5 proceeding, the participants to those proceedings, includi ng the

Commission staff, must adhere to the guidance and direction of the policy statement and

direction of the policy statement and develop a record consistent with the content of the

policy statement in all particulars.14 For examples of such boiler plate notice, see, for example, CNG Transmission Corp., 51

F.E.R.C. ¶ 61,267, Tennessee Gas Pipeline Co., 51 F.E.R.C. ¶ 61,113, and National Fuel Gas

Supply Corp., 48 F.E.R.C. ¶ 61,121.

15 Id. While this language is perhaps less precise than it should be, we do not think that the Commission

intended these statements to indicate that the initial rates were provisional. Rather, the Commission

meant that, just because the init ial rates were based on MFV, TETCO would not be precluded from

seeking Commission approval in a § 4 or § 5 proceeding for future SFV-based rates.

Once the Commission approves init ial rates, they generally stay in effect until a pipeline files

for a change in the rates in a § 4 proceeding and the Commission determines that this change is just

and reasonable. S ee, e.g., Texas-Ohio Pipeline, Inc., 69 F.E.R.C. ¶ 61,145 ("The ra tes approved

herein are init

ial rates under NGA section 7.... These initial rates will remain in effect until such time

as Texas-Ohio files an NGA section 4 general rate proceeding...."). If the Commission wishes to

make rates provisional, it will expressly condition them as such. S ee, e.g., Texas E. Transmission

Corp., 51 F.E.R.C. ¶ 61,384 (1990) ("Texas Eastern's rates are placed into effect subject to refund,

which wi ll protect Brooklyn Union, should it ultimately prevail."). If the Commission expressly

permits higher rates on some condition and that circumstance comes to pass, the Commission may

no t refuse to permit the higher rates on the grounds of the filed-rate doctrine. S ee Natural Gas

Clearinghouse v. FERC, 965 F.2d 1066, 1074 (D.C.Cir.1992) (noting that Commiss ion adopted

pipeline's express reservation allow ing it the right to seek a surcharge "subject to" a pending rate

challenge, and that, once the pipeline won the challenge, this surcharge could be imposed even on gas

already sold).

We do no t view the Commission's general statements about SFV and MFV as expressly

conditioning its determination that TETCO can only impose SFV-based init ial rat es. Similar

statements can be found in other orders, and largely amount to general notice that the Commission

may permit future rates to be based on SFV. 14 In fact, the Commission has stated that any changes

in rate design based on the policy statement

will be effective prospectively from the date of a final Commission order on the issue in the16

individual proceeding. This is because one of the Commission's objectives is to design rates

that give pricing signals that will affect current behavior. This purpose is not achieved by

retroactive price adjustments.

Interstate Natural Gas Pipeline Rate Design, 48 F.E.R.C. ¶ 61,122 (1989).

It is certainly true that the MFV-based rates set forth in the June 1989 certificate order could

not be considered "final" if TETCO—like Transco—had requested a rehearing and then, if necessary,

had sought further review. However, TETCO did not do so. Thus, TETCO must evident ly be

arguing here that the Commi ssio n, using the language quoted at the beginning of this section,

expressly conditioned its imposition of MFV-based rates by putting the parties on notice that it might

in the future unilaterally require these rates to be based on SFV. This is wholly unpersuasive.

Moreover, the Commission's interpretation of its own certificate is entitled to considerable deference.

See Mitchell Energy Corp. v. FERC, 651 F.2d 414, 417 n. 9 (5th Cir.1981) ("The Commission ' s

construc t io n o f it s certificates is entitled to great weight and commensurate deference."). The

Commission's finding that the MFV-rates in its June 1989 certificate order were final is not arbitrary

or capricious, and is supported by substantial evidence.

2

TETCO next contends that the customers had adequate notice that the Commission might

permit SFV. TETCO argues that the Commission erred by finding that, because TETCO failed to

ask for a rehearing after the June 1989 certificate order, the customers had no notice that they might

face SFV-based init

ial rates. Moreover, it suggests that the agreements and the June 1989 certificate

order itself provide adequate notice of such a possibility.

The Commission determined that the "mere fact" that TETCO failed to file a t imely petition

for rehearing of the June 1989 certificate order meant that its request to apply SFV to the init ial rates

would violate the filed-rate doctrine. Apparently, the Commission interpreted T ransco as standing

for the proposition that, once an order allowing MFV becomes final, the customers have "no notice"

of the possibility of SFV.

We beli eve that this discussion is misleading. T ransco simply observed that a petition for17

rehearing can put customers on notice that SFV "might ultimately prevail." T ransco, 54 F.3d at 898.

It did not suggest that a rehearing request was the only means to ensure notice in such a situation.

If this were so, rates could o nly be increased starting from the date the request was filed, not, for

example, from the date set forth in a preexisting contract. This is not the law. T ransco as well as

CPUC, Columbia II, Consolidated Edison Co. of N.Y., Inc. v. FERC, 958 F.2d 429 (D.C.Cir.1992)

(" ConEd "), and other cases make clear that the Commission must look for adequate notice from a

variety of sources, including agreements with customers and Commission orders. See CPUC, 988

F.2d at 216 (stating that, when determining whet h er Commission order violates the filed-rate

doctrine, the court "inquires whether, as a practical matter, the purchasers of the gas

... had sufficient

notice that the approved rate was subject to change"); C onEd, 958 F.2d at 434 (ruling that where

p is adequately served); C olumbia II, 895 F.2d at 796-97 (noting that Commission itself can put

parties on notice t hat t he rates they will be paying are subject to retroactive adjustment at a later

date). Moreover, it is certainly a rguable here that, given the fact that the June 1989 certificate order

was final, the customers had notice that the Commission might unilaterally decide to allow such rates

later. Hence, we will examine whether the customers received notice of this possibility from either

of the two sources TETCO cites, the certificate order itself and the agreements.

TETCO claims that the certificate order put the customers on notice of the possibility that the

Commission might permit SFV-based init ial rates. It points to the Commission's various comments

in the order suggesting that the SFV/MFV issue was in flux. However, we do not believe that these

remarks put the customers on notice that the Commission would permit TETCO to apply SFV to the

init ial rates after these rates became final. Rather, the Commission merely signaled that it might allow

TETCO to use SFV in some later § 4 or § 5 proceeding (or on rehearing), or that the Commission

might itself endorse SF V in t he fut ure. We believe that, after the certificate became final, the

customers would have been surprised if the Commission had authorized SFV-based init ial rates. S ee

Gulf States, 1 F.3d at 292-93 ("No t o nly did [the customer] have actual notice of increases in [a

factor used to calculate an equalization charge], but there appears to be no dispute that the proposed15 We note that the D.C. Circuit cases, unlike Hall and this case, all involved an argument that

the Commission violated

the filed-rate doctrine, rather than the claim that it should not have

applied it. However, we do not believe that this difference affects our analysis of adequate

notice.

16 True, the agreements provide that the customers would pay SFV-based rates as filed with

FERC, "and as same may hereafter be legally amended or superseded." But since the Commission

has rejected SFV-based initial rates in this case and they have never gone into effect, this

provision does not control.

18 changes are provided for by the ... agreement.... In short, the filing [for a rate increase] could not

have come as a surprise" to the customer.). These vague, ambiguous policy statements are simply

not up to the task of providing adequate notice. C f. Transw estern, 897 F.2d at 580 (finding that

preamble to regulations asserting purpose of assuring pipelines the recovery of all purchased gas costs

did not provide customers with adequate notice that a pipeline could recover costs from a customer

after the system governed by the regulations ended, and noting that "the Commission's assertion of

a po licy go al in one context is hardly the same as a rule implementing that goal in every other

context").

Next, TETCO contends that the parties' agreements provided adequate notice of SFV. As

support, it points to various cases in which courts have held that the parties' agreement to a particular

rate "overcomes" the filed-rate doctrine. These include a Fifth Circuit case, H all, as well as a number

of D.C. Circuit cases, ConEd, CPUC, Natural Gas Clearinghouse, Columbia II, and Piqua. 15 We

agree that, under these cases, the contracts provided notice to the customers that the Commission

might impose SFV. We note, t hough, t hat in each of these cases, the aggrieved party sought

rehearing of the order permitting or refusing to permit higher rates. In other words, these orders

never became final, at least until the parties exhausted the appeals process. In this case, though, once

TETCO failed to request a rehearing of the June 1989 certificate order, that order did become final.

Once the certificate order became final, it would certainly be reasonable for the customers

to assume that the Commission would not unilaterally revisit the order and impose SFV-based init ial

rates. 16 "[A] certificate supersedes any contract to the contrary." C olumbia Gas Transmission Corp.

v. FERC, 750 F.2d 105, 110 (D.C.Cir.1984). Moreover, "[b]y accepting a certificate of public17 It is true, however, that two or three years later the customers again became aware that

TETCO wanted the Commission to allow it to impose SFV-based initial rates. In July 1991, for

example, TETCO sought rehearing of the Commission's June 1991 rehearing order permitting

Transco to use SFV, and asked the Commission to grant it the same relief as Transco. However,

such belated notice is irrelevant. Relying on the final MFV-based initial rates, the customers had

already made their purchasing decisions for the period in which the initial rates were in effect.

19 convenience and necessity a gas company agrees to perform the service authorized therein, even if

that service is not required by the underlying contract." M itchell, 651 F.2d at 417. Thus, while the

agreements originally provided the customers with notice of the possibility of SFV-based init ial rates,

once the MFV-based initial rates became final, this notice "vanished." 17

While TETCO only indirectly raises the issue, we also do not believe that the Commission had

any record of unilaterally substituting rate designs and imposing them retroactively on customers, and

t hus do no t believe that the customers could have received notice from any Commission practice.

See CPUC, 988 F.2d at 166 (stating that Commission's record of granting take-or-pay charges was

a factor providing notice that pipeline's certificate conditions were subject to change); C onEd, 958

F.2d at 434-35 (noting that Commission's record of granting requests for retroactive effective dates

was a factor giving notice). In fact, as discussed above, the Commission has explicitly stated in the

context of the policy statement that it would not retroactively impose a new rate design. I nterstate

Natural Gas Pipeline Rate Design, 48 F.E.R.C. ¶ 61,122.

We also think it is important here that the customers in this case had no notice during much

of the period when they were making purchasing decisions invol ving t he init ial rates. A major

underlying purpose of the filed-rate doctrine is predictability. T owns of Concord v. FERC, 955 F.2d

67, 75 (D.C.Cir.1992). It permits "purchasers of gas to know the consequences of the purchasing

decisions they make." I

d. Moreover, a principal purpose of the filing provisions of NGA is to give

advance notice of proposed rate changes to the customer. C f. Union Tex. Prods. Corp. v. FERC,

899 F.2d 432, 433 (5th Cir.1990) (same with regard to Federal Power Act); see also ConEd, 958

F.2d at 434 n. 7 ("Noting the identical language and purposes of the Federal Power Act and Natural

Gas Act notice provisions, the Supreme Court has cited them interchangeably.") (citing Arkla, 43318 TETCO suggests that the fact that Transco sought rehearing of the June 1989 certificate

order should have put the customers on notice that the Commission might permit TETCO to impose SFV-based initial rates. However, like the downstream purchasers in Columbia I,

TETCO's customers were simply not the appropriate audience for Transco's rehearing petition.

See also CPUC, 988 F.2d at 164 (stating that "relevant audience" must be placed on notice).

Where both Transco and TETCO had the right to seek rehearing of the certificate, and only

Transco exercised that right, TETCO's customers would hardly expect that the Commission might

modify the certificate as to TETCO.

19 In Transco, the court found that the Commission erred in determining that allowing

SFV-based initial rates would "defeat the legitimate expectations" of various customers because

"the Commission never explained what legitimated those expectations" and it never considered

the expectations of customers who might have relied on the agreements. Transco, 54 F.3d at

899.

In this case, though, permitting SFV-based initial rates would defeat the customers'

legitimate expectations. The Commission properly found that the customers lacked

20 U.S. at 577 n. 7, 101 S.Ct. at 2930 n. 7).

In a typical § 7 situation, parties agree on a particular service and on proposed ra tes, the

service begins, and the Commission decides whether to allow the service and what the rates will be.

The "norm" in such a situation is that the Commission's "finall y det ermined rate" will be applied

starting from the date of init ial service. T

ransco, 54 F.3d at 899. This is because the parties'

agreements precede the date of init ial service and thus the customers are "on no tice [about thi s

increase] from the outset." C PUC, 988 F.2d at 164. Such a "retroactive" increase does not violate

the filed-rate doctrine because the customer knows from the agreements that it may face SFV and

thus canificant that the customers only had notice of the possibility of SFV-based init ial rates from

the date of the agreements to about five months before the init ial date of service (i.e., the date when

the init ial rates began to accrue) and then again, at the earliest, some twenty months after the init ial

rates were superseded by new rates. 18 Therefore, the customers lacked notice of the possibility of

SFV-based init

ial rates when they were making purchasing decisions based on the final MFV-based

init ial rates. In other words, as the Commission found in its June 1993 order, the customers must

have relied—and quite reasonably—on the finalit y of the June 1989 certificate order (rather than on

the agreements to which the Commission did not give effect) to try to calculate the consequences of

their purchasing decisions. 19 The filed-rate doctrine exists to provide just this sort of predictability.adequate notice of the possibility of SFV-based initial rates because TETCO failed to

request rehearing of the June 1989 certificate order. Surely, customers would legitimately

expect that they could rely on a final order of the Commission in making their purchasing

decisions. We cannot reasonably assume that customers will base their purchasing

decisions on the possibility that the Commission will unilaterally modify a final order

governing those decisions.

20 As public utilities, the customers must try to keep their gas purchasing and transportation

costs as low as possible. Relying on MFV, the customers would have compared TETCO's

commodity charges to its competitors and chosen the pipeline with the lowest ones.

Alternatively, relying on SFV—a 100 percent demand charge—the customers would have wanted

TETCO to meet as much of their supply needs as possible. Thus, imposing SFV-based initial

rates after the period in which initial rates were in effect would overturn the customers' least-cost

purchasing decisions and raise their expenses.

21 It seeks to prevent customers from relying on certain rates, only to find later that their purchasing

decisions have been upset and their costs increased. 20

In sum , we find t hat the customers lacked adequate notice that the Commission would

unilaterally authorize SFV-based init ial rates and that, while the customers may have originally had

adequate notice of possible SFV-initial rates, they lacked adequate notice during the time it mattered.

Therefor e, we det ermine that the Commission's finding that the customers did not have adequate

notice is not arbitrary, capricious, or lacking substantial evidence.

Accordingly, given our conclusion that the Commission did not err in finding that the

MFV-based init

ial rates in the June 1989 certificate order were final and did not err in finding that the

customers lacked adequate notice of the possibil it y o f SFV-based initial rates, we affirm the

Commission's decision to apply the filed-rate doctrine in its August 1995 order.

IV

TETCO also argues that the Commission erred in fin ding in its August 1995 order that

"[c]hanging our prior authorization [of SFV in the March 1992 order] does not actually change the

financial position of any of the parties. While TETCO's expectations are left unmet, reversing our

1992 decision now leaves TETCO in exactly the same position it was in prior to that order." 72

F.E.R.C. ¶ 61,152.

As the Commission conceded in its August 1995 order, the March 1992 order did not specify22

whethe r TETCO could charge SFV rates on a retroactive or prospective basis. However, when

TETCO filed tariff sheets in April 1992 that would allow it to impose SFV rates retroactively, the

Commissi o n reject ed them in its June 1993 order. Thus, the March 1992 order never went into

effect, and no final order existed p ermit t ing TETCO to charge SFV-based initial rates. In

comparison, in the August 1995 orde r, t he Commission noted that the March 1992 order, while

unclear, could only have had retrospective effe c t because new rates superseded the init ial rates on

December 1, 1990. The Commission then ruled that the filed-rate doctrine barred it from permitting

TETCO to charge such retrospective rates. Thus, TETCO i s in exactly the same position now as it

was before the March 1992 o rder; it still must use MFV-based initial rates. Accordingly, the

Commission's finding that the March 1992 order did not change the parties' financial position is not

arbitrary, capricious, or lacking substantial evidence.

V

TETCO con t ends t hat the Commission erred in its June 1993 order by considering the

customers' untimely "Request for Clarification" of the March 1992 order, and then erred in the June

1993 and August 1995 orders by effectively negating the March 1992 order.

As discussed above, 15 U.S.C. § 717r(a) confers broad power on the Commission to

reconsider, modify, and even set aside any order issued under the NGA. It states that

[u]ntil the record in a proceeding shall have been filed in a court of appeals

... the Commission

may at any time, upon reasonable notice and in such manner as it shall deem proper, modify

or set aside, in whole or in part, any finding or order made or issued by it under the provisions

of this chapter.

Whether the Commission reconsiders and changes one of its orders sua sponte or in response to a

belated suggestion

fro m a party is irrelevant. In T ennessee Gas Pipeline Co., 871 F.2d 1099

(D.C.Cir.1989), for instance, the court held that the Commission could modify an order in response

to an untimely "Motion for Clarification."

It is true that, in its June 1993 order, the Commission "clarified" its March 1992 order in a

way that effectively overruled it. At that time, however, no record had yet been filed with this court,

and TETCO had reasonable notice that the Commission mi ght issue such an order given the21 TETCO also appears to challenge the substantive findings in the June 1993 order. However,

it is unclear what, if any, findings from the June 1993 order survive the August 1995 order. In the

later order, the Commission merely stated that it had made unspecified mistakes in the June 1993

order and affirmed its "result" on different grounds.

Because we affirm the Commission's judgment in the August 1995 order, we need

not reach the question of whether the Commission erred in making the various specific

findings in the June 1993 order.

23 customers' motion. Thus, the June 1993 order was in no way p rocedurally defective. Similarly, the

fact that, in the August 1995 order, the Commission took a "fresh look" at the case and determined

that "mistakes were made" in the March 1992 and June 1993 orders is perfectly proper. Also, the

fact that it decided to affirm the "result" of the June 1993 order on somewhat different grounds and

to reverse explicitly the March 1992 order is likewise permissible.

While we appreciate the parties' confusion in attempting to guide their conduct by orders that

the Commission has conceded were "mistake[n]," we har dly think that § 717r(a) precludes the

Commission from correcting its errors and clarifying its reasoning. 21

VI

For the foregoing reasons, we AFFIRM the judgment of the Commission.