Towing with our Wrangler

Just kind of an FYI regarding towing with our '99 Wrangler TJ.
When we rented the Camp Inn 550 in June I was very happy with the way it towed behind our Wrangler. That was part of the prerequisite for going ahead with the purchase of a Camp-Inn trailer. However, one factor seemed rather odd for towing a trailer - I swear we gained fuel mileage! We normally average about 15 mpg empty with the TJ. I checked after our outing that weekend and found we got about 16 mpg. Our Wrangler is equipped with the 4.0 I6, 5 spd, 4.10 gears, 3" lift and mildly aggressive 33x12.50 tires. It's not built for great gas mileage. This past weekend we went on a 300 mile total mile camping trip with our, (new to us), 560 Raindrop. On the first portion of the trip we used 9.6 gal for 157 miles...over 16 mpg! On the return trip we got around 15.5 mpg. We also made numerous stops on the way back. This result is not the same for our '08 Jeep Liberty which dropped from about 19 mpg to 14. Whether by plan or accident, the Camp Inn is very friendly to our Wrangler and that's just dandy with us! -Terry