Yes TBM, you are on the money there.
The thing about Restricted CAT is that it does limit their operations. Some agencies want their aircraft to be in Charter in order to be used for RAFT (and other acronyms!) teams etc. This means they will get a twin-engine helicopter in Charter Cat that may not have a lot of performance, even though, say, a Black Hawk in Restricted Cat would have much more performance in the case of an engine failure in the hover while winching.
So yes, the lawyers run the show!