I drive a lot in the mountains. One thing I've noticed in my short ownership experience is the car seems to gain more range over extended downhills than it loses on the same hills, going uphill. For example, yesterday I drove from home near Denver to Arapahoe Basin ski area (great ski day, BTW), going from 5500 to 11000 ft ASL. I used about 100 miles of range for the 70 mile drive uphill. Coming home, I used about 30 miles of range going downhill, for a net gain of 10 miles. I've noticed similar effects on another drive I regularly do with about a 3000 ft elevation change. Is this simply an artifact of the range calculations? If not, how is this possible.