Kontact I still feel safer saying that because the seat tube angle changes that the saddle might not be at the same distance from the vertical axis off of the BB. I'm not going to assume that because the head tube angle and other things change too that simply measuring from the bars to the saddle will give the same setback.

But I can only assume from you wishing to say I'm wrong that you must think it will always be at the proper setback no matter what bike or model or size. Or do you actually measure to put the saddle the same distance back from the vertical axis of the BB?