Okla. Stat. tit. 12A § 2-307
Unless otherwise agreed all goods called for by a contract for sale must be tendered in a single delivery and payment is due only on such tender but where the circumstances give either party the right to make or demand delivery in lots the price if it can be apportioned may be demanded for each lot.
Okla. Stat. tit. 12A, § 2-307
Oklahoma Code Comment
There are no previous Oklahoma decisions precisely on this point. See, however, Wolfe v. Texas Go., C.C.A., 83 F.2d 425 (1936), certiorari denied 299 U.S. 553 , 57 S.Ct. 15, 81 L.Ed. 407, in which it is held that in the absence of an agreement, payment is due on delivery and Robberson Steel Co. v. Harrell, C.A., 177 F. 2d 12 (1949), in which it is held that when the contract calls for delivery in installments the default of the purchase in the payment of earlier installments is a sufficient breach to justify the buyer's refusal to make additional deliveries.