Does the SBC sometimes send more calls than configured in the SA constrains?

In a client I've configured the session-agent to have a maximum of 100 simultaneous sessions. Setting max-sseions to 100 and constraints to enabled in the Sesson-Agent config.

But when I input the command "show sipd agents [agentwithconstrains]" it shows 113 in the High Lifetime Outbound sessions. It was a day with a lot of calls and I could see many calls returned with a error (the expect operation, blocking the calls that exceed the constrains)

But for what I know it means that the maximum simultaneos sessions was 113. Why it surpassed the constrains of 100? Maybe the SBC sent more calls than it should have due to the high CAPS? Maybe the metric is not right? Maybe near the limit of 100 calls, the SBC sends more calls to the SA than it should because the rate of incoming calls is faster than the answer time of 100trying/180ringing.