I didn't choose the 83% number casually, though I do appear to have mis-remembered by one percent. Unless you think the EPA data is falsified?
210/249 = 84.3%
218/259 = 84.1%
200/238 = 84.0%
Even if you had been right, my basic point would stand - charging a 60 to 100% is not the same as charging a 75 to 90%.
I'm not doubting your math skill, I'm letting everyone know the hard numbers are out there. The EPA numbers are not great sources because they allow for other factors to be involved. I can explain those factors via PM if you need more info.
The ACTUAL usable capacity of each battery is available via the techniques used in the long WK057 thread. I was too lazy to go look up the exact figures, but it's 62.X and 72.X. This information is valuable to purchasers, because the "90" kWh is also actually significantly less than claimed, while the "100" was truely 100kWh in usable capacity IIRC.
The "60" isn't larger than 60 by mistake...it is the capacity required to provide the X60 with 200 mile range.