Initially, I wondered if the…
Initially, I wondered if the vehicle had continued to charge off of power ( like how your food continues to cook when you take either out of a microwave), but now I see it makes perfect sense the BMS has looked at 97% charge and says you get X and has then overnight compensated mileage for charge.
I suppose It is no different to being in an ICE vehicle, and your range when you start says X and will vary depending on how heavy your right foot is.
As an example, I drove 300+ miles last week and on stopping my Range said I still had 400 + when I got back into the vehicle in the morning that number had changed