Hi.
This is a very good question, and one I have asked before implicitly but still await any sort of usable answer, and I have given up all hope of ever getting one. As such, I would be VERY curious for an answer from Automic, too.
If you have the same contracts we have, you are required to send license usage data to Automic, and generate that data with the license reporting tool. The thing has always been, the data you send with that tool seems to have historic usage data in it, and someone at Automic has analyzed it further according to rules which are a black box to the customer. I can tell from experience that they at least once did include past usage of agents that were uninstalled by the time the figures were reported. Then in the end they used to tell the client whether he is compliant or not. There is literally no way for me to predict by which rules Automic counts the usage, and it has been made worse by the removal of the license overview, because now I can't even see what Automic thinks I am using at any given time. Furthermore, Automic has recently stated it will not send us a compliance statement anymore at all, so all bets are kinda off.
Ultimately, this comes down to a legal question much more than a technical one. I ensure I never use more agents than I am licensed to, and am in the comfortable position to always have a small buffer as well (free cash to Automic, yay!), and feel pretty safe with the legal framework of my country if Automic were ever to tell me that we were not compliant because of past usage overlaps.
But you need to make that judgement for yourself.
Consider the following: an agent not present AWI will probably not be subject to the counting in the license reporting tool. But an agent that starts up once reports it's presence to the engine, and Automic might count that as a used license already (for an unspecified past period as outlined above). Also, legally speaking, the only surefire way is to entirely uninstall the agent and totally remove all of it's files from a machine, since Automic could always make the case that the mere presence of the startable files constitutes an installation. Most EULA (and I think the one we have for Automic, too) say that you need to fully purge the software from a machine, so I would use that as a guideline if you want to be absolutely safe.
Disclaimer: I am not a lawyer.
Best,
Carsten