Hi Navin,
Kind of a side note, but your service profiles will only need a reboot if the new boot policy is check marked for "Reboot on Boot Order Change". This can be handy if the new boot policy stays consistent with what device is actively booted to the system, and only differs with things like vMedia mounting.
Specific to your original question, with UsrAck set in the maintenance policy, and the new boot policy being flagged, my expectation was that it would be the individual affected components, but wasn't certain that it wouldn't trigger a larger Ack of all dependent components.
To test it I created an equivalent boot policy with Reboot on Boot Order Change, and changed one of my templates to point to this. The resulting Pending Activities does show the capacity to individually remediate the impacted servers:
On yet another side note, I confirmed another aspect of the behavior I expected, where an OS initiated reboot of one of the affected servers does clear the Pending Activities flag for that server within UCSM. As you'll see below, a reboot of one of my blade-3 server through its installed OS has cleared it from the list:
Hope this helps.
-Ramesh