A device 'shutdown' feature delay time,
or zero if none, used by system administrators of this device.
Usage: The time delay after last 'shutdown' trigger event
(eg, completion of the last 'energy save' cycle to 'sleepMode')
before the 'shutdown' cycle will begin (to power 'offMode'
in 'xcmHrDevInfoConditions' and 'down' in 'hrDeviceStatus').