Worked after trying different tire heights
So it works great, but required trying different tire heights to get it right. First I compared speeds using my hand held GPS unit and it was off after entering the manufacturer spec of my tire. I learned this is not the height I should use, but rather the height of the tire measured from the ground to top of tire with weight of the vehicle on it. My tire according to the manufacturer measures 33.98", however with the weight of the truck on it, it actually measures just under 33".
Exactly what I needed
I purchased a different controller at a higher price. It caused the check engine light to come on and it surged when idling. I spent (6) 20 minute unsuccessful attempts to talk to their customer service without any success. I ordered the Hypertech. Everything was programmed in 10 minutes with the Hypertech. I've owned another Hypertech unit for 8-10 years and it still works perfect. I don't know why I didn't get Hypertech first. I love my Hypertech and so does my truck.