The RADIUS interim accounting is received I think every 600 seconds (5mins) so we need to ensure that the 200MB in your example has been reached before we would trigger the enforcement profile for a user. Its possible that a user will have used their 200MB but we haven't received the interim updates.
Can you follow a user/endpint session in the access-tracker please.... as the interim updates come it you will see on the accounting tab (confirm you have this as you said acc is working) the usage updating as we post the details we get from the interim acc updates to the access-tracker session for a user/endpoint. Lets get an absolute YES that the details are coming in and being added to a session as expected.
You said ACC was working, but lets check interim ACC is working.... ensure interim ACC is enabled in CPPM also please.