Indiana Code Title 24. Trade Regulation § 24-4.5-2-108

(1) the seller may permit the buyer to purchase goods or services on credit either from the seller or pursuant to a seller credit card;

(2) the unpaid balances of amounts financed arising from purchases and the credit service and other appropriate charges are debited to an account;

(3) 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

(4) the buyer has the privilege of paying the balances in installments.