The CWB implementation of SCCS is more basic than its implementation of (T)CCS; for example, I have given up on trying to keep parameterised agents available in both, and I haven't ported the AgentExtra functionality, although it wouldn't be hard. I have very limited time; SCCS in the CWB has just got knocked down the priority stack. If you would like to take over development of the SCCS module, please send me an email!
Remark: I once saw a draft of a book (Introduction to the Formal Design of Real Time Systems) by David Gray which purported to use SCCS. However, that draft badly misrepresented SCCS, and as far as I'm aware I never managed to persuade the author to correct the book. So if you are discovering discrepancies between the CWB's behaviour and what that book suggests, please consult Milner's definition before reporting a bug in the CWB!