TFL Truck highway MPG test 2500 Cummins

My 2014 4x4 averages a hair under 20 on the highway running 65 - 70 on cruise. Step up to 75 and it drops down to 17 - 18. DEF usage is about 500 to 700 mpg. The 4WD trucks do sit a little higher and I have a RanchHand front bumper, tool box, and headache rack (all hurt air flow) so I suspect his mileage is pretty realistic. I have been very happy with the mileage, it is a little better than my old 2005 GMC Sierra 1500 overall, with almost the same cost per mile for fuel as the old truck. Maintenance will be higher, but it will tow a LOT more.