2-36.5 Lease, Rental, and Lease-Purchase Contracts To determine whether the purchase of products by lease, rental, or lease-purchase contract (including lease-to-ownership, or lease-with-option-to purchase) is covered by the WTO GPA or an FTA, calculate the estimated purchase value as follows: If a fixed-term contract of 12 months or less is contemplated, use the total estimated value of the purchase. If a fixed-term contract of more than 12 months is contemplated, use the total estimated value of the purchase plus the estimated residual value of the leased equipment at the conclusion of the contemplated term of the contract. If an indefinite-delivery contract is contemplated, use the estimated monthly payment multiplied by the total number of months that ordering would be possible under the proposed contract (i.e., the initial ordering period plus any optional ordering periods). If there is any doubt as to the contemplated term of the contract, use the estimated monthly payment multiplied by 48.