2007, 2500, 4x4, 6.7, 6 speed auto , 3.73 axles
Combined hwy/city = 15.5 to 16.5. I consider that to be pretty good especially since the company truck (2009 F250 Powerlessstroke) only gets 14mpg on the highway at 70.
Don't believe the overhead, at least on my truck it's too optimistic.