Lots of "figuring" in here that just doesn't hold true.
You can charge to 100% and use that range literally whenever you need to. That range is not lost to you and you should use it whenever you want. A few 100% charges may actually get you "back" some miles from your BMS having a more accurate picture of your battery's actual capacity.
70-80% efficient is simple to achieve. 90-95% is pretty easy too on long trips. Averaging 340wh/mi in a Model 3 puts you WELL above what most people see. In 100k miles, I've averaged 315wh/mi in my much less efficient Model S.
As they say, "your mileage may vary".
Set your display to percentage instead of miles and watch your worries melt away.
from my understanding the displayed range DOES NOT take into account your driving style or temp and bases it off the estimated battery capacity left. Also, the BMS can be off, and if it’s off the car will shut down when the displayed range gets to zero even if the battery actually has more capacity.
Am I wrong here? If I ask Tesla 5 times I get 5 different answers so I don’t know.
If I am right then setting it to % and forgetting about it would be a bad idea. If I’m wrong (which I hope), then it’s definitely the best idea.