Hi Julian,
In Home page we see license usage prompt message based on License APs Usage Threshold (5-100): setting in AMP Setup > General page.
Example if we have 100 license and set threshold to 90, once Airwave license usage reaches 90 it will prompt message that 90% of your licnese been utlized.
In your case license usage exceeded and we no longer able to add new deivces to Airwave. You could montior and mange all your 17 devices.
Note: We allow few devices even license usage got exceeded but later we no longer able to add or discover devices.
Regards,
Pavan
If my post addresses your query, give kudos:)