; (ii) that is used for enrollment in a course of study necessary for enrollment in a program leading to a degree or certificate, shall be equal to, from the principal amount of the loan, 20 percent of the amount of such loan; (iii) that is used for enrollment in a program that is necessary for a professional credential or certification from a State that is required for employment as a teacher in an elementary or secondary school in that State, shall be equal to, from the principal amount of the loan, 20 percent of the amount of such loan; and (iv) that is a Federal Direct PLUS Loan made on behalf of a dependent student or used for enrollment in a graduate or professional course of study, shall be equal to, from the principal amount of the loan, 35 percent of the amount of such loan. (C) Reduction due to prepayment (i) In general In order to provide an incentive to borrowers to pay the balance of a loan made under this part earlier than required under the applicable repayment plan, the Secretary may credit or refund any such borrowers for an amount of the financing fee charged under this subsection. (ii) Regulations (I) In general Not later than 9 months after the date of enactment of the Leveraging Opportunities for Americans Now Act of 2023 , the Secretary shall promulgate regulations establishing the methodology for crediting or refunding a financing fee charged under this subsection pursuant to clause (i). Such credit or refund shall not reduce the financing fee by more than— (aa) with respect to a borrower whose income, as determined under subclause (II), was not more than $45,000 in the taxable year in which the borrower paid an amount from the balance of a loan made under this part earlier than required under the applicable repayment plan, 15 percentage points of such amount