Subsidiary services
(4) Subsidiary services(i) In general. Services related to a sale or lease of export property are subsidiary to such sale or lease only if it is reasonably expected at the time of such sale or lease that the gross receipts from all related services furnished by the DISC (as defined in subparagraphs (2) and (3) of this paragraph) will not exceed 50 percent of the sum of (a) the gross receipts from such sale or lease and (b) the gross receipts from related services furnished by the DISC (as described in subparagraph (2) of this paragraph). In the case of a sale, reasonable expectations at the time of the sale are based on the gross receipts from all related services which may reasonably be expected to be performed at any time before the end of the 10-year period following the date of such-sale. In the case of a lease, reasonable expectations at the time of the lease are based on the gross receipts from all related services which may reasonably be expected to be performed at any time before the end of the term of such lease (determined without regard to renewal options).