Reliability of adjustment for differences in volume. (i) FS manufactures product XX and sells that product to its parent corporation, P. FS also sells product XX to uncontrolled taxpayers at a price of $100 per unit. Except for the volume of each transaction, the sales to P and to uncontrolled taxpayers take place under substantially the same economic conditions and contractual terms. In uncontrolled transactions, FS offers a 2% discount for quantities of 20 per order, and a 5% discount for quantities of 100 per order. If P purchases product XX in quantities of 60 per order, in the absence of other reliable information, it may reasonably be concluded that the arm’s length price to P would be $100, less a discount of 3.5%. (ii) If P purchases product XX in quantities of 1,000 per order, a reliable estimate of the appropriate volume discount must be based on proper economic or statistical analysis, not necessarily a linear extrapolation from the 2% and 5% catalog discounts applicable to sales of 20 and 100 units, respectively ...