How are licenses counted?

How are licenses counted?

I would like an explanation about how licenses are counted in Desktop Central. When are licenses consumed and when do they get released? I cannot seem to find any information regarding this in the documentation.

I would also like an explanation of these lines from the "License" popup window:

- Number of Systems
- Number of Mobile Devices:
- Number of Technicians:
- Managed Systems:
- Enrolled Mobile Devices:
- Added Technicians:

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