Neb. Rev. Stat. §§ 45-339
Where a buyer makes any subsequent purchases of goods or services from a seller from whom he has previously purchased goods or services under one or more installment contracts and the amounts under such contract or contracts to the extent of cash sale price thereof have not been fully paid the subsequent purchases may be included in and consolidated with one or more of the prior contract or contracts. A memorandum of such additional purchases shall be prepared by the seller and inserted in or attached to the seller's counterpart of the contract and shall set forth:
A copy of such memorandum shall be delivered to the buyer as provided in and subject to the provisions of section 45-336. When such subsequent purchases are made, the entire amount of all payments made prior to such subsequent purchases shall be deemed to have been applied on previous purchases.
Each payment thereafter made on a consolidated installment contract shall be deemed to be allocated to all of the various purchases in the same ratio or proportion as the original cash sale prices of the various purchases bear to one another. Where the amount of each deferred payment is increased in connection with such subsequent purchase, the subsequent payments, at the seller's option, may be deemed to be allocated as follows: An amount equal to the original installment payment to the previous purchase, the balance to the subsequent purchase. The amount of any initial payment or downpayment on the subsequent purchase shall be allocated in its entirety to such subsequent purchase. The provisions of this section shall not apply to cases involving equipment, parts, or to other merchandise attached or affixed to goods previously purchased, or to repairs or services in connection therewith rendered by the seller at the buyer's request.
Neb. Rev. Stat. §§ 45-339