Section 17. A. A holder may by agreement with the buyer refinance the unpaid balance of a single retail installment sale agreement, refinancing agreement or consolidation agreement to provide for a new schedule of the times or amounts of the payments or both.

B. A refinancing agreement, as described in paragraph A shall be in writing, and shall be dated and signed by the parties, and

(1) May provide for a finance charge which shall not exceed the rates provided in section eleven applied to the sum of (a) the unpaid total of payments of the agreement being financed, less the refund credit for finance charge provided in section thirteen and (b) any additional cost for continuing insurance coverage under the agreement being refinanced and for official fees;

(2) Shall incorporate by reference the agreement being refinanced and shall clearly set forth and itemize the unpaid total of payments being refinanced, the refund credit, the amount to be refinanced, the finance charge, additional cost for insurance or official fees or both, the total sum payable under the refinancing agreement, the amounts and times of installment payments, annual percentage rate;

(3) Shall comply with the provisions of subsection A, clauses (1) through (5), inclusive, of subsection D, and subsection E of section nine, and of sections ten, eleven, twelve, thirteen, fifteen and twenty-one; and

(4) Shall not include within the amount financed, as defined by section one of chapter one hundred and forty D, any amounts representing the consideration for any transaction, retail installment sale, loan, or other extension of credit other than the retail installment sale then being refinanced.