I go off the EVIC to get general MPG info, you would have to reset the EVIC on the different terrains you drive, and even that is not accurate enough. So on my trip to Salt Lake I let the EVIC just average out over the the entire trip. But I watched the MPG display to see my current MPG and could see improvements, or not, on different terrains. I was pleased to see an occasional 19 on the EVIC for an average. But once I started climbing towards Denver the MPG dropped quick. The Rocky's was surprisingly better than expected, the climbing MPG was averaged out by the decent MPG and was @ 18ish. Its quite a climb from Kansas to Denver, not enough to really feel but it shows up with poor MPG.