Tracking Time spent on Support calls

Tracking Time spent on Support calls

Here is the problem I'm trying to solve, hoping you guys can help.

Currently we are offering Packaged or Bundled support where a customer prepays 8 hours of support. Now what I want is for my techs to track the time spent on calls using the time tracking tab. My question is if they're using the time tracking tab how can I run a report to show the hours spent or where can I pull up a report showing me time spent on calls per tech?

Or is there a possibly another way to handle this?

Thanks in Advance