Section 1431(a) of the Dodd-Frank Act amended TILA section 103(aa)(1)(B), 15 U.S.C. 1602(aa)(1)(B), to provide that a mortgage is a high-cost mortgage if its total points and fees exceed a certain percentage of the ???total transaction amount,??? rather than the ???total loan amount.??? TILA section 103(bb)(1)(A)(ii).