I do create reviewer and product owner users in aha.io automatically via the REST API. If I create a product owner and this exceeds the current available paid seats I get an exception.
It should be possible to read the amount of available paid seats via the API and if no paid seats are available anymore, to update the paid seats and provision the product owner user as expected.
Thank you for the idea. Given the low volume of support for this idea, we do not have plans to make updates in this area at this time. We hope you can understand.