Section 13L. Except as otherwise provided in section one hundred of chapter one hundred and forty, section sixteen of chapter two hundred and fifty-five B, section nineteen of chapter two hundred and fifty-five C, and subsection B of section thirteen of chapter two hundred and fifty-five D, if a loan contract, for personal, family or household purposes, is prepaid in full by cash, a new loan, refinancing or otherwise before the final installment date, the borrower shall receive a refund of the precomputed charges computed on a method which is at least as favorable to the borrower as the actuarial method, so-called. If prepayment is made other than on an installment due date, it shall be deemed to have been made on the first installment due date if the prepayment is before that date, and in any other case it shall be deemed to have been made on the next preceding or next succeeding installment due date, whichever is nearer to the date of prepayment. Where the amount of the credit for anticipation of payment is less than one dollar, no refund need be made.