(e) Comparable sale means any sale of or bona fide offer to sell the same commodity, or (in the absence of such a sale or offer to sell) any sale of or offer to sell a similar commodity which, with respect to the quantity, quality, grade, period of delivery, supply area, terms of sale, or class of purchaser, either:
- (1) Is not sufficiently different from the sale being tested to result customarily in a price different from the price in the sale being tested; or
- (2) Can be related to the sale being tested through application of a customary price differential. A sale which is otherwise comparable to another sale is not rendered noncomparable by virtue of its being made out of a free port or bonded warehouse. The fact that a sale is made out of a free port or bonded warehouse shall not cause that sale to differ from otherwise comparable sales with respect to terms of sale, supply area, or period of delivery.