Well CMS wouldn't understand the workload ( vols x AHT ), all it does is once the wait time for any call goes above the threshhold (e.g 30 secs) it would take it out of queue for the primary/top agents and re-route it to secondary/reserve agents, now there are 2 scenarios resulting from this
1) all your primary agents are busy, calls get rerouted after specified time to available reserve agent and gets answered ( you will have to set the patience threshhold lower than your contracted ASA for e.g if your contracted asa is 80% in 20 secs then you may have to assign 10 secs for the patience level to enable it to reroute the call to reserve agent)
2) all your primary agents are busy, calls get rerouted after specified time to reserve agent however even all reserve agents are busy, then the call is kept in queue and moment any of the top or reserve agent comes in avail mode its served to them.
Let me know if you need more clarifications |