I've installed mine, and I experienced the similar results. At first right after changiny my tires to 285's I was getting 14-15 mpg, and with a few slight adjustments I've been averaging 17-18mpg, and I'm hoping to reach the 20+ mark soon. It's a slow process of tuning it, but it's going to pay off in the long run thanks to Alans work on this.

Chris