I wonder if I am confused about Optimized Battery Charging? If I plug in my MBP and it charges to 100% and I leave it plugged in (almost 16 days now) will it never go down to 80%? I would expect the MBP to be smart and even if plugged in it would use the battery to allow it to go down to 80%. Do I need to unplug it and let it go below 80% and then plug it in so that it will charge to 80% and stop? I tried that a week ago, but it didn't work. It was under 80%, I plugged it in, and it charged up to 100% again and it has remained that way.