One shows total average MPG and the other is based on that tank of fuel. When you fill up the tank based one will reset. I tend to just have the total average showing, currently 48.1 MPG (UK). Hope this helps.There is the one next to the current meter...the meter that moves left and right as your efficiency goes up and down...then, there is the one that just shows average MPG (which is usually 1 or 2 MPG less than the first one I mentioned). I think one is the running total and the other resets (not sure if it resets automatically or not) when you fill up the car with gas. Any help on this...also, noticed I am getting better mileage now than the first 100 miles put on car...just broke 300 today and have a little less than a half tank left...according to my miles left to empty, it shows I should get about 505 miles on a tankful...I think that is because my miles per gallon increased as I drove it more...I do find I am driving slower than with my SUV but from what I hear, most people that get hybrids drive like that in the beginning to see how it all works (mileage, meters on car, etc). Loving the car though...so far. I thought I heard a little rattle noise coming from under the glovebox but when I looked under there, it seems that when they installed the light up door sills, the panel was screwed in ok but it stuck down a little and needed to be popped back into place on the very left side under the glovebox at the lowest point above the passenger floormat....did that and don't hear the noise anymore. It was a slight buzz sound at low speed (like 15-20 MPH)...anyway, noise is gone.