Okla. Stat. tit. 14A, § 14A-3-203: Delinquency charges

(1) With respect to a precomputed consumer loan, refinancing,

or consolidation, the parties may contract for a delinquency charge

on any installment not paid in full within ten (10) days after its

scheduled due date in an amount not less than Five Dollars ($5.00)

nor more than any of the following, whichever is greater:

(a) five percent (5%) of the unpaid amount of the

installment,

(b) the dollar amount provided by rule of the

Administrator for this section pursuant to Section 1-

106 of this title, or

(c) the deferral charge (subsection (1) of Section 3-204)

that would be permitted to defer the unpaid amount of

the installment for the period that it is delinquent.

(2) A delinquency charge under paragraph (a) of subsection (1)

may be collected only once on an installment however long it remains

in default. No delinquency charge may be collected if the

installment has been deferred and a deferral charge (Section 3-204)

has been paid or incurred. A delinquency charge may be collected at

the time it accrues or at any time thereafter.

(3) No delinquency charge may be collected on an installment

which is paid in full within ten (10) days after its scheduled

installment due date even though an earlier maturing installment or

a delinquency charge on an earlier installment may not have been

paid in full. For purposes of this subsection payments are applied

first to current installments and then to delinquent installments.

(4) If two installments or parts thereof of a precomputed loan

are in default for ten (10) days or more, the lender may elect to

convert the loan from a precomputed loan to one in which the loan

finance charge is based on unpaid balances. In this event he shall

make a rebate pursuant to the provisions on rebate upon prepayment

(Section 3-210) as of the maturity date of the first delinquent

installment, and thereafter may make a loan finance charge as

authorized by the provisions on loan finance charge for consumer

loans (Section 3-201) or the provisions on loan finance charge for

supervised loans (Section 3-508A), whichever is appropriate. The

amount of the rebate shall not be reduced by the amount of any

permitted minimum charge (Section 3-210). If the lender proceeds

under this subsection, any delinquency or deferral charges made with

respect to installments due at or after the maturity date of the

first delinquent installment shall be rebated, and no further

delinquency or deferral charges shall be made.

(5) With respect to a consumer loan, refinancing or

consolidation, which is not precomputed, including a revolving loan

account accessed by lender credit card or similar arrangement, the

parties may contract for a delinquency charge on any installment not

paid in full within ten (10) days after its scheduled due date in an

amount not less than Five Dollars ($5.00) nor more than the greater

of five percent (5%) of the unpaid amount of the payment or the

dollar amount provided by the rule of the Administrator in effect

for this section pursuant to Section 1-106 of this title. No more

than one delinquency charge may be imposed in each billing cycle and

it may be collected at any time after it accrues either

independently of any payment made on the account or from a payment

made if the lender discloses delinquency charges to the debtor as

they are imposed and informs the debtor of the full amount that the

debtor must pay for the applicable period in order to remain current

on the account.