Okla. Stat. tit. 12A, § 4A-204
(b) Reasonable time under subsection (a) of this section may be fixed by agreement as stated in subsection (b) of Section 15 of this act, but the obligation of a receiving bank to refund payment as stated in subsection (a) of this section may not otherwise be varied by agreement.
Oklahoma Code Comment
A customer may obtain a refund of the amount of an
unauthorized payment order. The customer may recover interest only if notification of the unauthorized nature of the payment order is given to the bank within a reasonable time. This "reasonable time" may be set by agreement, but the obligation to refund may not be varied. It appears that the rate of interest could be set by agreement or even be waived.
Historical Data Laws 1990, SB 641, c. 110, § 12, eff. July 1, 1991; Amended by Laws 2005, HB 2028, c. 139, § 35, eff. January 1, 2006 (superseded document available).