Salary proration using actual working days

Summary:

Requirement for proration using scheduled working days in the month

Content (required):

A client has a requirement for salary proration based on scheduled working days in the month.

For example, an employee is scheduled to work Mon/Tue/Wed each week. In June 2023 that means 12 working days in the month.

If they were hired on 19th June, they would actually work 6 days in June 2023 (19/20/21/26/27/28). So their salary would be (annual / 12) * (6 / 12).

The trouble is that HCM only holds their work schedule from their hire date. Before 19th June it isn't there against the employee, so you can't work out that there would be 12 theoretical working days in June using that work schedule, and therefore can't do the proration calc. Obviously the same difficulty applies to an employee terminating mid-month also.