My Proximity Mute setting reverts between power-ups

If you set the Proximity Mute at Startup option to ON, you may notice that while Proximity Mute is enabled at power up, it comes up set to Balanced. 

If you prefer another Proximity Mute setting for the 'quiet zone' range, you need to first set that range, then set Proximity Mute at Startup to Last Setting. That will save all the Proximity Mute advanced settings for next time you power up.