The programming of the tank size only comes into play with the Miles to Empty computations.....The fuel tank sending unit registers correctly the volume without any changes to it.

 

^^^ This is correct ^^^^
I had my MTE reprogrammed for a 50 Gal tank, but it is not necessary.
If I did it over, I would skip the reprogramming.
The fuel sender still sits in the same place, there's just more fuel around it.

 

Yeah I understand just wondering. Although I am one of those guys that wants everything working correctly. It would drive me bananas if the miles to empty or the fuel used gauge wasn't working correctly.