Due Date Arrival: Invoice due date is reached Phase Transition: System automatically identifies invoice as past due (mission type changes to "Overdue") Interval Scheduling: External server schedules first overdue email for due date + send interval (e.g., 3 days after) Send Time Check: At your configured Daily Send Time, if triggered, email is composed and sent Placeholder Replacement: Subject and body placeholders replaced with actual invoice/customer data, including {days_overdue} calculation Email Dispatch: Email sent to customer with "From" address set to your company email Recurring Schedule: Next overdue email scheduled for due date + (interval × count), subject to stop conditions Stop Condition Check: After each send, system checks if email count limit OR day limit reached; if so,