707(b)(2)(A)(iii)(I) in a chapter 7 case is therefore as relevant as one addressing the issue in a chapter 13 case. The trustee has given no reason why section 707(b)(2)(A)(iii)(I) should be interpreted differently in chapter 7 and chapter 13 cases.
[2] The deduction was not an option. Section 1325(b)(3) says the expenses of an abovemedian debtor "shall be determined" under section 707(b)(2)(A) and (B). 11 U.S.C. § 1325(b)(3). Section 707(b)(2)(A)(i) then directs a calculation under which the debtor's current monthly income is "reduced by the amounts determined under clauses (ii), (iii), and (iv)," 11 U.S.C. § 707(b)(2)(A)(i), and section 707(b)(2)(A)(iii) says the debtor's average monthly payments on account of secured debts "shall be calculated" in accordance with sections 707(b)(2)(A)(iii)(I) and (II). Although context sometimes suggests otherwise, the word "shall" in a statute typically means "must." Gutierrez de Martinez v. Lamagno, 515 U.S. 417, 432 n. 9, 115 S.Ct. 2227, 132 L.Ed.2d 375 (1995).