I used an SCT livewire tuner with custom tunes and it did have the tire size setting in the tuner. It was a 2010 Ford F350 6.4L diesel and was a monster. My odometer still was off. The fuel calculator was WAY off with the tune.
I'm also wondering, if you change your gearing, tire size etc... how far off is your fuel calculator that you are showing in your picture. I can't imagine that is accurate. I have a hard time believing that you can get 14-15 mpg with a lifted truck with 37" tires when my factory truck with 32" tires and 3.92 gears is getting on average 15. It is new and I know mileage will get a little better, along with driving style for some but I think there is somehting off with the mileage calculation. I would love to think that I could add big tires and not hurt my actual mileage that much, but realistically I think I am looking at a couple mpg atleast by going to 35-12.50 tires.