2016 31DS and 2016 Jeep Cherokee Trailhawk....5K pounds. We see 7.5 to 8.5 and speed is more of a factor than even mountain passes. If we are running over 65 we are at the 7.5 range at 55 to 60 or so we see the 8.5.
The Jeep is stealthy, I still find myself yelling at the tailgater until I realize it's the toad. (oops)
As an interesting comparison, I had a 2011 Tundra with the 4.6 V8 and pulled a 25' travel trailer. Almost identical mileage, so I think that makes the Ford V10 a tad more effecient at pulling.