Lookforshooter - How often do you fly a true performance-limited TO? That is, given the runway/pressure altutude/obstacles/OAT etc., you could not legally carry one pound more, for performance reasons?
If you ever did, and compared that to an average FLEX TO at standard day SL conditions, you'd find the FLEX TO gave you quite a bit more margin than the true performance-limited case. Why? Because your TAS (inertial speed - see Newton's third law) is lower because the wing is flying in cooler/denser air.
There's a science to this business, Lookforshooter, and name-calling does nothing to help your case.