Staffing wasn't a factor. When we had 13 CPCs, we had 4 or 5 on a shift running 2 hours on, 2 off. I guess the could've collaborated and said they would like to split off ground and fd/cd if staffing wasn't a factor and gotten the crwg number up to 30. The point being there was no accountability in verifying the needs of these facilities if you can have 2 identical facilities arrive at 2 wildly different crwg numbers.
And yes, CIC is part of the job to "when necessary, supplement the supervisory staff." It's not meant to be built into the target numbers to staff a standalone CIC for the whole day. We were more than capable of working CIC and our 2 planes on the scope concurrently.