Section 622 - Refund for prepayment of contractA. The buyer, notwithstanding the provisions of any installment sale contract, shall have the privilege of prepaying at any time all or any part of the unpaid time balance under an installment sale contract.B. Whenever all of the time balance is liquidated prior to maturity by prepayment, refinancing or termination by surrender or repossession and re-sale of the motor vehicle, the holder of the installment sale contract shall rebate to the buyer immediately the unearned portion of the finance charge. Rebate may be made in cash or credited to the amount due on the obligation of the buyer.C. The unearned finance charge to be rebated to the buyer shall represent at least as great a proportion of the total finance charge as the sum of the periodical time balances after the date of prepayment bears to the sum of all the periodical time balances under the schedule of payments in the original agreement: Provided, however, The holder shall not be required to rebate any portion of such unearned finance charge which results in a net minimum finance charge on the contract less than ten dollars ($10.00); And provided further, the holder shall not be required to rebate any unearned finance charge when the amount due, computed as herein set forth, is less than one dollar ($1.00).1947, June 28, P.L. 1110, § 22. Amended 1949, May 2, P.L. 812, § 2.