2015 F-150 Mileage Display/Fuel Usage Wrong

I'm posting here first to keep this forum going. It was one of the first and I'm confused by the lack of use anymore. Anyway...
Just got this F150 two months ago. The internal indicator for fuel usage is always a gallon off. I get 19.5 gallons on the pump and it says I used 18.5. So the mileage calculation it does is off 5% every time from my own calculation. Is there anyway to adjust this, or is this part of the reason someone is suing Ford for misrepresentation of mileage? It says I'm getting 22 highway, but I'm actually getting 21. Not a big difference, but it does drive me up the wall that it isn't correct. Based on my usage, it will say I used 100 gallons ($239 today's price here) a year less than I actually did.

Almost no fuel mileage calculator an any vehicle is correct. It is a guess based on load, throttle position, RPM, etc. I've had vehicles where it said I got 25 mpg on a road trip, but when I did the math I actually got 28. I had it say I got 23 mpg, but I only got 19. In my F250 I drive for work it pretty much always says I got 12.9, but if I am hauling I might only get 11, but if I am on a long highway run and not hauling I might get 14.

I did some hunting and found there is a way to adjust this. Here is a link to changing it.
https://www.f150forum.com/f118/fix-inaccurate-mpg-display-2-minutes-421912/
For my truck I calculated I will enter 948 in the AFE Bias and see how things go.