Bev, I looked for info on this in Making Trousers for Men & Women by David Page Coffin. Under the heading "Shaping the Legs" on pp 117-118, he talks about being told by a tailoring expert to "ease the fronts to the backs above the knee and the backs to the fronts below the knee." However, he says he tried it and saw no difference in either wearing comfort or drape of the finished pants. He feels that any shaping that's done in constructing pants is negated when the pants are worn. Coffin's research on methods tends to be pretty extensive -- he examines RTW and hand-tailored garments, then tries techniques several times before writing about them, so when he says he's tried this and it makes no difference, I'd suspect that it's been tried with several different fabrics and in several different styles (trousers, slacks, etc.), and I'd be pretty confident that it really doesn't make a difference. He acknowledges that Sandra Betzina is the only contemporary sewing writer who discusses shaping pants during the construction process, and that her book Power Sewing Step-by-Step "has some interesting suggestions," so you might want to check that out also.