Sustained at more voltage = more degradation. There no way around that according to their own graphs. To put some number on it, my Mac has been plugged in 100%

Sustained at more voltage = more degradation. There no way around that according to their own graphs. To put some number on it, my Mac has been plugged in 100% for a few hours and is at 12.951V or 4.32V per cell which is very high and the graphs show it will degrade quickly at that voltage. So even with this feature, I'm still negatively affected by keeping it plugged in. For the record, my Mac is at 6553mAh of 6871mAh which is really 95% which implies the feature is on and active and still at 4.32V!