Actual concurrent managers are more than Target concurrent managers

Dear Experts,

In My environment actual concurrent managers are exceeding the target concurrent managers, It is happening for standard managers and inventory managers. There is no PCP.

Ex: Suppose if there are 20 standard managers as target, there are 23 Actual managers.

At that time suppose 30 programs are submitted it is taking 23 programs to running even it's actual target is 20.

I have tried increasing and decreasing the work shifts of these managers to make it equal, But still the actual managers are more than target.

I have queried the fnd_concurrent_queues table,  I've observed that RUNNING_PROCESSES and TARGET_PROCESSES are equal at back end for these managers.