Did you actually see that behavior with the 2013 model? My experience so far with a 2014 Model Suggests that the GOM displays a certain asymmetry. It seems very responsive to increases in energy expenditure. E.g. if I start out with 95 mi (warm weather) and then drive somewhere at 80 mph, the range drops very quickly (minutes) to 50-something (and falling). OTOH, if I then start doing some low speed urban driving, the range recovers more slowly - e.g. range might at first increase a few miles fairly quickly then level off, recovering ~1 mile per mile driven (or a bit more if I'm really taking it easy). Topping up the battery might then get it to 80-85. Range recovery seems to slow down after the initial ~1mile/mile. It usually takes a few days of efficient driving for the GOM to completely recover from a lead foot episode. However, I rarely drive more than 20 miles/day. I figure it's been taking ~40 miles of low power driving to counter the effect of 10-15 miles of high power driving, but only a few miles of high power driving will cut the range estimate dramatically if it started out high.