A. Payments made on retail charges agreements, open-end contracts or similar types of add-on retail sales agreements shall be first applied to the purchases earliest in time. The payments shall be credited first to the current interest or carrying charges and then in reduction of the purchase price of merchandise in the order in which it was purchased.

B. When, subsequent to the date of purchase, payments have been made and credited in an amount to pay the sales price and carrying charges of any merchandise, then that article of merchandise shall be considered paid for in full, provided that all balances incurred prior to that purchase have been paid.

C. The articles of merchandise which have been paid for under this section shall not thereafter be repossessed or considered security for the payment of any charges arising out of subsequent purchases under the same account.