(a) Every revolving account shall be in writing and shall be completed prior to the signing thereof by the retail buyer. The printed portion, other than instructions for completion, of any revolving account shall be in at least six-point type. Any such account shall contain the names of the seller and the buyer, the place of business of the seller, and the residence or place of business of the buyer as specified by the buyer, and substantially the following notice in clear and conspicuous type:

"Notice to the Buyer

Do not sign this before you read it or if it contains any blank spaces. You are entitled to an exact copy of the paper you sign. You have the right to pay in advance the full amount due."

A copy of any such account shall be delivered or mailed to the retail buyer by the retail seller prior to the date on which the first payment is due thereunder. Any acknowledgment by the buyer of delivery of a copy of the account shall be in clear and conspicuous type and, if contained in the account, shall appear directly above the buyer's signature. No account shall be signed by the buyer when it contains blank spaces to be filled in after it has been signed. The buyer's acknowledgment, conforming to the requirements of this subsection, of delivery of a copy of an account shall be presumptive proof in any action or proceeding of such delivery and that the account, when signed, did not contain any blank spaces as provided in this subsection. A revolving account shall be presumed to be signed or accepted by the buyer if, after a request for a revolving account, such revolving account or application for a revolving account is in fact signed by the buyer or if such revolving account is used by the buyer or if such revolving account is used by another person authorized by the buyer to use it. The revolving account is not effective until: the buyer has received the disclosures required pursuant to the federal Truth in Lending Act, 15 U.S.C. Section 1601, et seq., as amended; the buyer or a person authorized by the buyer uses the revolving account; and the seller or its assignee extends credit to the buyer for transactions on the revolving account.

(b) Notwithstanding any other law, the seller under a revolving account may charge, receive, and collect a time price differential which shall not exceed 17.5¢ per $10.00 per month computed on all amounts unpaid thereunder from month to month (which need not be a calendar month) or other regular period. If the amount of time price differential so computed shall be less than $1.00 for any such month, a time price differential of $1.00 for any such month may be charged, received, and collected. If the regular period is other than such monthly period or if the unpaid amount is less than or greater than $10.00, the permitted time price differential shall be computed proportionately. Such time price differential may be computed for all unpaid balances within a range of not in excess of $10.00 on the basis of the median amount within such range if as so computed such time price differential is applied to all unpaid balances within such range.