For each consumer credit transaction other than under an open end credit plan, the creditor shall disclose each of the following items, to the extent applicable:
If a consumer credit sale is one of a series of consumer credit sales transactions made pursuant to an agreement providing for the addition of the deferred payment price of that sale to an existing outstanding balance, and the person to whom the credit is extended has approved in writing both the annual percentage rate or rates and the method of computing the finance charge or charges, and the creditor retains no security interest in any property as to which he has received payments aggregating the amount of the sales price including any finance charges attributable thereto, then the disclosure required under subsection (a) of this section for the particular sale may be made at any time not later than the date the first payment for that sale is due. For the purposes of this subsection, in the case of items purchased on different dates, the first purchased shall be deemed first paid for, and in the case of items purchased on the same date, the lowest price shall be deemed first paid for.