It's a subtle transition from the closing charge to benediction. I uncover at the mention of Deity: "... and may the G... " and recover after "Amen - So mote it be." Then the questions to the Wardens, and uncover again at "... may the blessing..." Hat back on after "So mote it be." Hat off at the mention of Deity in the closing order, then recover.
Sounds like a bit of a drill, but they're trying to inculcate into us new guys that the Master puts his hat on when he walks into the lodge room, and it only comes off at specific times: during prayer, mention of Deity, reading of Scripture, pledge of Allegiance, reading of a brother's death notice, and when yielding the East to a grand lodge officer.
Me, still learning...