If the monthly rate of basic educational assistance allowance otherwise payable to an individual under
section 3015 of this title increases during the enrollment period of a program of education for which an accelerated payment of basic educational assistance is made under this section, the charge to the individual’s entitlement to basic educational assistance under this chapter shall be determined by prorating the entitlement chargeable, in the matter provided for under paragraph (1), for the periods covered by the initial rate and increased rate, respectively, in accordance with regulations prescribed by the Secretary.