The total principal amount of new loans made and installments paid pursuant to lines of credit (as defined in section 292o of this title) to borrowers covered by Federal loan insurance under this subpart shall not exceed $350,000,000 for fiscal year 1993, $375,000,000 for fiscal year 1994, and $425,000,000 for fiscal year 1995. If the total amount of new loans made and installments paid pursuant to lines of credit in any fiscal year is less than the ceiling established for such year, the difference between the loans made and installments paid and the ceiling shall be carried over to the next fiscal year and added to the ceiling applicable to that fiscal year, and if in any fiscal year no ceiling has been established, any difference carried over shall constitute the ceiling for making new loans (including loans to new borrowers) and paying installments for such fiscal year. Thereafter, Federal loan insurance pursuant to this subpart may be granted only for loans made (or for loan installments paid pursuant to lines of credit) to enable students, who have obtained prior loans insured under this subpart, to continue or complete their educational program or to obtain a loan under section 292d(a)(1)(B) of this title to pay interest on such prior loans; but no insurance may be granted for any loan made or installment paid after September 30, 1998. The total principal amount of Federal loan insurance available under this subsection shall be granted by the Secretary without regard to any apportionment for the purpose of chapter 15 of title 31 and without regard to any similar limitation.