Seems that everyone always gets better mileage than me, no matter what I'm driving.
I'm an easy driver too, with easy starts off the line and for cruising at 57mph and just enough to prevent downshifting into 5th going over grades.
I'm at 16tons and over a 13yr period, among three owners, my average is 6.2 on the OEM digital dash readout. I tow as well and was only able to increase this average by 0.1 over four years.
Not even sure, if this is counting the genset, since I don't know where sensors for this is.
I've also noticed that some of these big rigs, get as much as our toad, all by itself. Ummmmmmm!