Microsoft quietly added a new preference for AutoUpdate last month that allows MacAdmins to override the length of the default 60 minute deadline timer. The preference works starting with version 4.48 of MAU.
More details about update deadlines and this timer are available in my article Forcing Microsoft Office update deadlines with MAU from July 2019.
The new preference key is “UpdateDeadline.FinalCountDown” and is under the “com.microsoft.autoupdate2” preference domain. The data type is an integer that represents minutes.
If you have any questions please join us in the #microsoft-autoupdate channel of the MacAdmins Slack.
Thanks to Darrin Pertschi for making me aware of this new preference.