(a) "Revolving charge account" means an arrangement between a seller and a buyer pursuant to which:
(i) The seller may permit the buyer to purchase goods or services on credit either from the seller or pursuant to a seller credit card;
(ii) The unpaid balances of amounts financed arising from purchases and the credit service and other appropriate charges are debited to an account;
(iii) A credit service charge if made is not precomputed but is computed on the outstanding unpaid balances of the buyer's account from time to time; and (iv) Either the buyer has the privilege of paying in full or in installments or the seller periodically imposes charges computed on the account for delaying payment and permits the buyer to continue to purchase on credit.