If the BMS gives “estimated” miles given your driving habits - is there any way to reset it? Lots of people have driving patters that change from time to time - depending on other cars they own, etc. It would be nice if the BMS didn’t try to anticipate your range based on past driving - and be able to tell it to “start over again.”
BMS doesnt give range estimates based on driving habits at all. It gives range estimates based on how much energy it THINKS is in the battery. It has a hard(er) time estimating maximum battery capacity if the battery is not charged past 80 percent due to how the voltage changes in the battery work (paraphrasing what I have read here, I am not an expert on this).
The TL ; DR version is, charging to 80% will be marginally better for the battery than charging to 90% over some indeterminate long time, with a small benefit, HOWEVER, charging to 80% will not let the car keep as good a tab on how much range it actually has, so it can sometimes display a lower number.
Also, charging it to 90% once wont allow the battery to balance. Charging it to 90% and letting it sit there for a while (plugged in) lets it do so. Most of the people with these "rated range" issues are normally "running down and then charging up" or, charging to 80% because everyone here tells them to.
Conversely, most people who plug in, charge to 90% and not worry about it, have minimal losses. With me as an example, my 90% charge is now 273 instead of 279, but I have 18k miles on my car. 6 miles "lost" over 1 year and 18k miles.
As for OPs specific concern, I dont quite understand it, but I dont have to, because its not my money.