Attempt to purchase the subscription with additional resources fails with an error message:
Table Subscription doesn't contain row with id Int32(NULL)
The service plan is based on the service template with option
One-time Fee Item enabled, subscription is not created for such plans. It shall not be possible to configure any additional resource rates for such plans.
Ambiguous software behavior is reported as bug with id #PBA-67653 ("Purchasing additional resources on a Service Plan with One-Time Fee causes error "Table Subscription doesn't contain row with id Int32(NULL)."").