When trying to remove a resource type of Application Service class, the following error is shown:
Error Resource type #ID xxx has non zero usage and can not be removed
When corresponding resource type instance was unprovisioned, for some reason it's usage was not updated for certain subscriptions. As a result those subscriptions still have non-zero usage of this resource type.
In order to fix the issue with the resource usage a manual database intervention is required. Please contact Odin Technical Support.