It would be great to have a filter per site/product on the User Counts administration page "admin.atlassian.com  > Products > User counts"

Then customers can setup and receive an update/email when the number exceeds a certain percentage per site/product. 

Now, we have included every product - not separated per site:

https://support.atlassian.com/organization-administration/docs/monitor-your-enterprise-user-counts/