If I get on top of Teton Pass and drive into Victor,Idaho I would probably get like 50 mpg (I have no idea what it would be, except very high). I am not going to then claim that I get 50 mpg, it is misleading and ridiculous. I could take a video of that and it would look good though. The vast majority (minus one 18.1 mpg claim on Fuelly) all are south of 15 mpg. That is still nothing to be ashamed of, big horses have to be fed. There is no value to anyone else when you cherry pick the most optimal driving conditions and claim the resulting mpg as your "mileage". Now if you want to qualify the statement with "when the stars aligns (going downhill with a tailwind), I can see 18 mpg" that puts your statement in a context that we can all relate to. Either way, you have a very nice pickup with big power, it is not necessary to be misleading on its mpg, it is what it is.