Furthermore, the construction of contract terms is circumscribed by specific rules of law. On these bases, we conclude that an agency's construction of a contract is subject to de novo review by this court. In this area this court has as much expertise as the PSC, if not more. We turn then to the language of the contract which set the rate for the penalty tariff to be imposed in the case of the unauthorized use of natural gas. The PSC concedes that the above language is ambiguous.
Ambiguity exists if a contract provision is reasonably susceptible to more than one interpretation.
The ambiguity outlined above underscores the arguments of both sides. The PSC interprets the tariff as not requiring the local distribution company to actually experience inadequate supplies and incur a penalty itself in order to charge double the pipeline penalty. It is a well-settled rule of contract construction that ambiguous terms in contracts are to be construed against the maker or drafter of the contract. See Dairyland Equip. A utility can only assess charges which are set forth in a properly filed tariff.