I purchased my 2013 Model S and the dealership had it advertised as a 60 but when I got in the car to test drive it I noticed that it said S 75 on the screen. I also saw that the range that was available was currently at 244 (not 100% charge). Was the 60 kwh battery just unlocked to 75 kwh? The guy at my local SC said the previous owner upgraded the battery at some point. Once the 60 kwh has been unlocked to a 75 does the display reflect that change or should it still say 60?