I agree - we can pretty much ignore the data from our first tank, unless you filled it up yourself when you left the dealer. On ours the gauge read full when we took possession, and there were 27 miles on the odometer, but we have no way of knowing if they filled the tank at 0 miles or 26 miles, and exactly how full they got it. Only when we have full control of the fill-ups can we get a reasonably accurate mileage reading...