When I first started here, I entered the readout from the display. Didn't really include a correction factor until the 5th tank. So don't sweat it...

My gas consumption spreadsheet tracks the lifetime MPG difference between pump and display automatically. Once I've decided what factor to use, it even scales all the tank MPG from display for me. That's the easy part actually, the real problem is that without support of a correction factor in the mileage database itself, you might need to go back and fix all previous tanks, possibly on every fillup. That's no fun believe me. So although I have the data to do this adjustment, I don't plan to adjust on every fillup, only once in a while.

In my case, it isn't that big a deal. My pump vs. display LPMG has always been pretty close. The display number is .19mpg too high at the moment. That's off by around .3% only.

Andy