Towing MPG???

I have actually gotten equal to better gas mileage towing than without... Now that I have your attention. I have a Ram 1500 Outdoorsman and until we get the TT, we are pulling the old 8 box pop up we've had for 11 years now. It is 1900 lbs loaded about a 200 lb hitch and is almost exactly the same height as the top of the truck bed with the bed tonneau and width of the truck. I'm thinking I'm getting some kind of positive wind flow along the whole set up as it moves down the vehicles since they are so close in size from a rear profile minimizing drag. Not that I am complaining. And the 5.7 hemi 3.92 gears kind of likes a nice light workout. That trailer doesn't hardly register and I can literally forget about it back there. Now this is distance highway driving without crosswinds. I think stop and go would not be the same.