The aerodynamic performance claims by manufacturers is probably the most dishonest topic that the bike industry is propagating on the general consumer, and doing it purely for sales, I know because I spent years in meetings with these same mfg's dreaming up lies about this stuff by using altered, or even fake data. Forums like weightweenies is where you'll find the sheep and fanatics that believe everything the manufacturers tell them like you'll be more aero or save so many watts with 2mm less here, much faster with 20g savings there. It's all collusion by the industry and the motive is profits, that's it.