Things to know in setting the API level:
1. If you're using the system's API settings, make sure that the API level is set to System.
2. If you want to use your own API, make sure to set the API level to Custom.
-- If you wish to set up Scheduling, make sure to use your own API level. The system's API settings doesn't support Scheduling.
If you have set that properly, you should be okay.
If not, let us know by submitting a ticket.
Have a great day!