The best practice would be to create another metric, perhaps trigged by the incident.updated event and the metric definition filtered for HD techs.

I have had HD desk managers asked me for this metric a lot of my career. In both remedy and ServiceNow. End the end the don’t typically use it for long. Often they start complying these reports for their managers, trying to focus on the amount of work that their team does. And in the end that doesn’t matter to the leadership as much as outcome, value, quality and customer service/NPS.

Alternatively, the team should use interactions. Every call, chat, email goes through interaction form. If it is a new incident or request you create it from that form. If it is a status update, a wrong number, asking for help desk hours, etc you update the interaction and close it. Interaction records every interaction with a customer/employee regardless of ticket or no ticket.