This is an extremely frustrating situation as I lost ~8% range overnight. Since I have a 2017 60D, this kind of loss is scary. I've already had to drive for hours in freezing weather with the heat off just to make it home on routes devoid of Superchargers. Route planning is already difficult, requiring me to add significant mileage to reach Superchargers along the way and sometimes I get home with ~11 miles in reserve.
Bottom line, the newer cars get increased mileage with software updates, but reverse for the older cars? I'm not happy.