Since it does not seem possible to automatically shutdown an instance in FME Flow Hosted, one workaround we found is to apply schedules to shutdown the instances. However, this is done manually and can be easily forgotten. A good way to ensure the instance has one is to suggest a schedule at the creation, with having a certain default value created.
Hope this makes sense, let me know if this sparks any more ideas or if you need further information on the subject!
