(2) This section does not limit or restrict the manner of calculating the sales finance charge, whether by way of add-on, discount, or otherwise, so long as the rate of the sales finance charge does not exceed that permitted by this section. If the sale is precomputed:
(a) The sales finance charge may be calculated on the assumption that all scheduled payments will be made when due; and
(b) The effect of prepayment, refinancing or consolidation is governed by the provisions on rebate upon prepayment, refinancing or consolidation, contained in section one hundred eleven of this article.
(3) For the purposes of this section, the term of a sale agreement commences on the date the credit is granted or, if goods are delivered or services performed ten days or more after that date, with the date of commencement of delivery or performance. Differences in the lengths of months are disregarded and a day may be counted as one thirtieth of a month. Subject to classifications and differentiations the seller may reasonably establish, a part of a month in excess of fifteen days may be treated as a full month if periods of fifteen days or less are disregarded and if that procedure is not consistently used to obtain a greater yield than would otherwise be permitted.
(4) Subject to classifications and differentiations the seller may reasonably establish, he may make the same sales finance charge on all amounts financed within a specified range. A sales finance charge so made does not violate subsection (1) if:
(a) When applied to the median amount within each range, it does not exceed the maximum permitted by subsection (1); and
(b) When applied to the lowest amount within each range, it does not produce a rate of sales finance charge exceeding the rate calculated according to subdivision (a) by more than eight percent of the rate calculated according to subdivision (a).
(5) Notwithstanding subsection (1), the seller may contract for and receive a minimum sales finance charge of not more than five dollars when the amount financed does not exceed seventy-five dollars, or seven dollars and fifty cents when the amount financed exceeds seventy-five dollars.
(6) Notwithstanding any provision of this section to the contrary, with respect to a consumer credit sale involving a motor vehicle or a mobile home or a consumer credit sale from the same seller of both a mobile home and the real estate upon which such mobile home is or will be located, or a consumer credit sale of a mobile home where a security interest in real estate owned by the buyer is given to the seller as collateral, a seller may from the effective date of this section until and including the first day of July, one thousand nine hundred eighty-two, contract for and receive a sales finance charge not exceeding eighteen percent per year on the unpaid balance calculated according to the actuarial method: Provided, That the quantity of real estate involved with the consumer credit sale of a mobile home upon which such finance charge is contracted for and received shall not exceed one acre.
(7) As an alternative to the loan finance charge allowed by section one hundred one, subsection (1) of this article, from the effective date of this subsection until and including the first day of July, one thousand nine hundred eighty-two, with respect to a consumer credit sale, other than a sale of real estate subject to the provisions of section one hundred two of thisarticle or a sale pursuant to a revolving charge account, a seller may contract for and receive a sales finance charge not exceeding eighteen percent per year on the unpaid balance of the amount financed calculated according to the actuarial method.