When a manufacturer steepens the seat tube angle as the frame size of a the same model gets smaller, do they compensate for the CG balance point by shifting the BB shell further forward or is the rider of the smaller size frame literally that much more over the BB than the larger size with a relaxed STA? I recently warrantied my older size 58 frame for the same model (newer design) and went with a size 56 as it was a more appropriate size for me and I feel as if I could use a little more setback. My new 56 has a 73.5 STA and my 58 had a 73 degree. Through the years on this model the 56's have always had .5 more of a degree steeper angle than the 58's. Why do manufacturers do this as I have read it is common? Wouldn't the smaller riders want the same CG balance point of the larger riders?