If your client gets disconnected and then reconnects quickly (< 60 sec), that would look like an additional connection from the provider's perspective since it would not have timed out yet.
pfSense can't run more than one instance of a specific client at a time (even if you wanted to), so if you only have four configured in pfSense then it can only be running four.
So either the provider is seeing a disconnected "ghost" session hanging around, or there is another client somewhere off pfSense connecting (local PC, perhaps? local lab setup?)