As a TT guy.........a ton of it is how the lump on top presents itself to the wind.

If I raised the stack by several inches and opened up my pad width on my TT "super bike" to a really really comfy more novice position I bet I would be slower on it than if I put my real good fit coordinates on an old tube framed fixed gear pursuit bike. No doubt. Basically 2019 TT superbike versus mid-90's tube frame pursuit frame.........the old school would be faster with the superior fit.