Any service managers or ex service mangers?

A parting thought before I bow out-

My industry (IT) has a propensity to seek "technological solutions for administrative problems".

IE something along the lines of- "I don't want to force employees to use their company provided email, so can you compile a spreadsheet of all the outside emails, feed it into our mail server, and keep it updated on a monthly basis?"

Instead of simply instituting an administrative policy of "you WILL use the company email for official business, and we WILL NOT accept that you did not receive an email at your private address as an excuse for any lack of communication".

Perhaps you could "just" administratively resolve the issue by paying your "good" techs better.

You could certainly use your metrics to validate why someone is or is not getting a bump to a higher pay grade without getting onto a semi-automated system of monthly bonuses.