So you are saying that hitched up the truck is 1/2" lower in the front? I used to do that because I think that it drives better but I think that you should be aware Ford does not recommend that. They actually want the front end higher than empty according to page 36 of the towing guide: https://www.fleet.ford.com/resources/ford/general/pdf/towingguides/Ford_Linc_18RV&TTowGuide_r8_May15.pdf
The only reason that I can think of for this is that they don't use a frame mounted hitch on the F150, just a glorified bumper hitch. They might be afraid that enough torque to pull the front end down will rip the bumper off. I admit that this is speculation on my part and would love for a Ford engineer to explain their reasoning but it hasn't happened yet.
