[CMS] Underutilized Report. What does this report fields mean?

Hello everyone

I'm running one of these CMS reports, called Software Underutilized. However, there are some fields I don't get what they exactly mean.

See pic below:

I understand the fields 'Application' and 'Total Installed', However, I don't get the meaning of 'Total Used' and 'Usage'. Numbers don't quite match in those fields

Thanks,