Obtaining the time interval between light agent updates

We're currently using On-Hold Time as our main metric when it comes to measuring how fast our internal teams are responding.

Currently, the On-Hold Time metric counts the cumulative time a ticket has spent in the On-Hold status.

We want to obtain the average difference in the intervals of the responses from our internal teams (through agent comments (either public or private)). How can we do this?

Thank you for your support!