What year is your F-250? Sometime around the 2010 time frame ford changed its recommendation on how much to return to the front wheels. This is using the fender well lip measurement method. The older recommendation, like for the '06 in my signature, was to return enough weight to the front end so the before and after measurements were the same. I believe the new recommendation is to return enough weight to the front end to recover one half of the difference between the before measurement and the after measurement. Folks with newer Fords, please correct me if that's not correct. The proper method is listed in the owner's manual for your truck. In my '06 manual there is no method listed using scale weights. I hope this helps you get the hitch set correctly.
Ken