Could be. However, I would think the computer wouldn't keep averaging the calculations on the display but rather constantly calculate from the total fuel used and miles driven. This way you keep accuracy since the calculation is fresh all the time.

Maybe I should work at keeping my mpg below 120 for a tank to see if the acuracy gets any better.

My hydroponics experiment

You ever notice how hard it is to lip read cartoon characters?
"Crazy is what the sane call Delta Flyer"