Oregon Revised Statutes Commercial Transactions § 83.140

(1) If, in a retail installment transaction, a retail buyer makes any subsequent purchases of goods or services from a retail seller from whom the buyer has previously purchased goods or services under one or more retail installment contracts, and the amounts under such previous contract or contracts have not been fully paid, the subsequent purchases may, at the seller's option, be included in and consolidated with one or more of the previous contracts. All the provisions of ORS 83.010 to 83.190 with respect to retail installment contracts shall be applicable to such subsequent purchases except as otherwise provided in this subsection. In the event of such consolidation, in lieu of the buyer's executing a retail installment contract respecting each subsequent purchase, as provided in this section, it shall be sufficient if the seller shall prepare a written memorandum of each such subsequent purchase, in which case the provisions of ORS 83.020, 83.030 and 83.070 shall not be applicable. Unless previously furnished in writing to the buyer by the seller, by sales slip, memorandum or otherwise, such memorandum shall set forth, with respect to each subsequent purchase, items required in ORS 83.030 (1) to (7), and in addition, the amount of the time balance owed by the buyer to the seller for the subsequent purchase, the outstanding balance of the previous contract or contracts, the consolidated time balance, and the revised installments applicable to the consolidated time balance, if any, in accordance with ORS 83.030. The seller shall deliver to the buyer a copy of such memorandum prior to the due date of the first installment of such consolidated contract.

(2) When such subsequent purchases are made, if the seller has retained title or taken a lien or other security interest in any of the goods purchased under any one of the contracts included in the consolidation:

(3) The provisions of subsection (2) of this section shall not apply to cases where such previous and subsequent purchases involve equipment, parts or other goods attached or affixed to goods previously purchased and not fully paid, or to services in connection therewith rendered by the seller at the buyer's request.