@Coupefan - The guess-o-meter tries to estimate your range. I've read that it's based on your use since you last restarted the car, but also since you last charged the car. So, if you charge to 100% and drive immediately on the freeway at 60mph for a few miles, it'll give you an estimated number based on that level of speed and acceleration. Then slow down, and drive on local roads for awhile, decreasing the power use for the same number of miles, and the car will recalculate and your range estimate will go up.
Ambient temperature changes can also change the guess-o-meter. As can use of the hvac system - turning on the hvac drops the estimated distance immediately.
The computer has some calculation based on charge percentage, hvac use, ambient temperature, recent use history (since recharge or since restart).
A hot car parked on a hot day after driving on the interstate with the AC on will have an estimated range that is different than that same car the next cool morning with the hvac turned off.
As far as charging, I have not been able to read if the charging percent is the percentage of charge as compared to brand new and fully charged, or the percentage of charge of what the battery is currently capable of storing, but i suspect it is the latter.