As I look at my list of some two dozen frames (don't ask why I have two dozen+ frames), I notice that ST to TT ratio seems to increase as the ST size increases.
So, a 50cm ST frame typically has a TT greater than its ST (TT = 52, even 54cm),
then when I get to the middle of the pack (ST=56 or 57) the TT matches (I think this is called "Square"? as in "a 56square is a 56STx56TT) then in the bigger frame sizes the TT drops down smaller than the ST (so a 62cm ST frame has a 59 or 60cm TT)
This can't be based on body dimensions.
Is there some constraint in framebuilding that makes this change in ST:TT ration change so?