When in the life of a ticket is the first reply time recorded?
The first reply time metric is calculated when the first public agent reply is added to a ticket. Know that this includes tickets which are created by agents. So tickets created by agents are not excluded from this calculation and if it takes a long time for the customer to reply and then the agent adds a reply back to them, that reply time could be longer than expected.
For more information, see Calculating first reply time.
If you are interested in finding the specific calculated values for the ticket metrics, you can look at our API Documentation here.