Titan replacement tank

I have a 2012 Ford F250 Diesel and I installed the 50 gallon Titan tank in my truck about 4 months ago. I did put the shield on it. I don't go off road however I just like the thought of a little more protection.:) The tank sits about 3" lower than the stock tank. Easy install took me about 4 hours. My stock tank was a 26 gallon and when hauling my AF 811 @ 12.5 miles to the gallon I was always looking for a fuel station. I had the Ford dealer reset my computer to have the miles to empty work correctly. However it is still off. I can run the distance to empty down to 20 miles and the gauge reading is sitting on E in the red and I still have 10 gallons in the tank. It's a great addition. It's nice to have 500 mile + range.