Okla. Stat. tit. 14A, § 14A-2-205

With respect to a consumer credit sale, refinancing, or

consolidation, the seller may by agreement with the buyer refinance

the unpaid balance and may contract for and receive a credit service

charge based on the amount financed resulting from the refinancing

at a rate not exceeding that permitted by the provisions on credit

service charge for consumer credit sales (Section 2-201). For the

purpose of determining the credit service charge permitted, the

amount financed resulting from the refinancing comprises the

following:

(1) if the transaction was not precomputed, the total of the

unpaid balance and accrued charges on the date of refinancing, or,

if the transaction was precomputed the amount which the buyer would

have been required to pay upon prepayment pursuant to the provisions

on rebate upon prepayment (Section 2-210) on the date of

refinancing, except that for the purpose of computing this amount no

minimum credit service charge (subsection (6) of Section 2-201)

shall be allowed; and

(2) appropriate additional charges (Section 2-202), payment of

which is deferred.