Calculating First Update Time after ticket was re-assigned to another group

Zendesk should introduce the way to track First Update Time after ticket was re-assigned to another agent/ticket group (e.g. when ticket was escalated to advanced support).

While First Reply Time is the most common metric to track the performance of first line support agents, there is no way to track First Update Time for advanced support agents (I say First Update Time as we might be interested in cases when the first comment after escalation is internal). Using recently introduced DATE_FIRST/DATE_FIRST_FIX did not solve this problem.

This is critical for tracking and optimizing the work of other teams than frontline support agents.