@NerakYak well, you don't need to create a custom event to trigger the email, custom events always bind with table which you create the event for and upon any changes such like insert/update or delete to perform specific action. since you already have a custom package deployed in client environment you can simply create a schedule task to execute every 4 hours as per the requirement.

In your custom package I believe you have a function already written to get the return values (0 or 1) so basically you can create a procedure in the declared custom package and inside that procedure do an IF statement to check your pre-written function returns value is equal to 0 then you can trigger the email sending by using Command_SYS.Mail(). Once in every 4 hours when the schedule execute it will check your return value whether 0 or 1 upon your return value, action will perform (in this case send an email).

Cheers!

AHA! I knew I was making it more complicated! THANK YOU!!

Glad that clarification helps you to fulfill your requirement.