2013 Ford F150 w/Factory Tow Package

Lone ranger, I tow with the same truck. I have the OEM tow brake set at 5.5 for most driving but turn it up to 6.5 for long hiway drives and downhills. Usually when I leave the house I hit the button and try for a light tug. What's your mpg? I'm at about 12.2 overall while towing and wondering how I compare.
Rgds, John

I'm not sure that the calibration settings are uniform from one controller to another.  I started with the control wheel completely off and rolled on what I thought might be a minimum setting-  maybe a quarter turn.  I then got to a safe, open space where I could simulate a "non-panic but serious" stopping situation.  (Approaching an intersection at a safe speed when the light suddenly turns.)  I was satisfied with my stopping distance, and haven't adjusted it yet.  (I take that back-  I must have inadvertently rolled the control wheel forward to the point that the trailer wheels locked up with next to no brake pressure.  Fortunately this did not occur in a critical spot.  I went back to my original setting and everything has been fine.