i am sure there is something to that,pro stock guys are well over an inch of lift ,but,they use a cam bearing for every pair of lobes,9 to be exact,,and their cam bearings I believe are 70-75 mm,HUGE,by any standards.where and when the actual flex comes into play would vary by combination of valve springs,rocker ratio,rpm,and such.us "normal" racers aren't looking for every ounce of horsepower at any cost either.i guess the best scenario would always be run what the manufacturer recommends and forget it.their history and r&d wouldn't lead you astray for sure,their reputation depends on it...........