I’m wondering about this too. The 100% charge range of 253 doesn’t say 90kw at all.
Pretty sure an upgrade would take a new pack. My P85 is at 255.
Dont forget this is a 2014 car
A brand new P90DL has an EPA rating of 270 miles. So 253 miles is 93.7% which means that the battery degradation has been of ~7% over the course of the 4 years / 40K+ miles. Which is not bad at all