As a customer support team lead I want to be able to estimate agent's performance with a SLA feature.

For instance, I create an SLA 60-second first response time trigger that shows me how often an agent answers within 60 sec (or another period).

This is more accurate compared with the first response calculation time itself. Because if I didn't answer 1 chat within 60 seconds I didn't hit SLA (my SLA percentage will be decreased correspondingly), but if I use the "first response time" metric and I reply to this chat within 30 minutes and other chats were answered within 60 seconds the average first response time will be 15+ minutes and I need a lot of chats to decrease this metric to 60 seconds.