contracts that were entered under subsection (c)(2) of section 9 of the Act of August 4, 1939 (53 Stat. 1194), to be converted under this section shall be converted to a contract under subsection (c)(1) of section 9 of that Act (53 Stat. 1195). (2) Prepayment Except for those repayment contracts under which the contractor has previously negotiated for prepayment, all repayment contracts under section 9(d) of that Act (53 Stat. 1195) in effect on the date of enactment of this Act at the request of the contractor, and all contracts converted pursuant to paragraph (1)(A) shall— (A) provide for the repayment, either in lump sum or by accelerated prepayment, of the remaining construction costs identified in water project specific irrigation rate repayment schedules, as adjusted to reflect payment not reflected in such schedule, and properly assignable for ultimate return by the contractor, or if made in approximately equal installments, no later than 3 years after the effective date of the repayment contract, such amount to be discounted by ½ the Treasury rate. An estimate of the remaining construction costs, as adjusted, shall be provided by the Secretary to the contractor no later than 90 days following receipt of request of the contractor