Has anyone validated the mpg readout on the Prius Prime with a full-empty drive? For example, start with a full gas tank, place the car in HV mode (depleted battery or save EV driving for before or after this test), reset a trip meter, drive until nearly empty, fill it up again. Calculate mpg by dividing trip meter miles by gallons filled and compare to trip meter mpg. After 2 such trips, the reading I get on the car seems to be higher than I calculate manually by about 4 mpg. I suppose for this question you could include the EV miles, but I'm doing the calculation leaving it out as to not artificially increase my HV-mode mpg estimation.
The Prius line has always had the problem of reporting higher than actual MPG on the dash. The last two generations of Prii were between 2 and 2.5 mpg higher than long term manual calculations would reveal. I don't care anymore to figure it out, as I have known the about the error for 8+ years. As long as I keep adding electrons to the battery, and not gas to my tank, I'm happy.
