OK, so on the other side of that coin you have a plane which weighs X... for 40 years your have been flying it on the assumption that it weighs X, you often fly it at it's max gross.... so why do you now say that some scales are right and u need to take 3 hours of fuel out of your tanks now? 40 years of flying say one thing.... why are you going against 40 years of flying. Margin you say... well call your useful load 250 lb and now you have only an hours worth of gas to worry about when you crash. I'm not saying fly unsafe, and im not saying skirt the rules... they r there for your and all of our protection... but 40 years of sucess is hard to argue with. Should you take that into account next cross country... sure, along with the temperature, runway, clouds, pressure, TBO, due point, fuel burn.... but isnt that why we fly? Fly safe, it's good for us all.