Notwithstanding section 683(b) of this title, the effective rate of interest after October 13, 1971, during the first five years thereafter of the term of any debenture purchased by the Administration from a small business investment company under authority of section 683(c) of this title, shall be the greater of 3 per centum or 3 percentage points below the interest rate determined pursuant to section 683(b) of this title. The Administration is authorized to apply interest paid to it by such company for the period from October 13, 1971, to October 27, 1972, without interest thereon, to interest payable after October 27, 1972.