A day the shop is closed is not a day the staff were absent, and payroll has to know the difference.
Pro-rata salary divides pay by working days. If the app does not know which days are non-working, either every closed day looks like an absence, or somebody adjusts the figure by hand each month — and hand adjustments are where payroll disputes start.
Setting the weekly offs once removes the correction. The register stops flagging closed days, and the salary calculation counts the days that were actually meant to be worked.
The days your business does not work.
Only for the days that count.
Working days are counted correctly.
Until the business changes its week.
Staff records, the daily attendance register, and the salary that comes out of it. Pay is worked out from the attendance already marked, with advances and weekly offs accounted for, rather than from a separate calculation.
Attendance is a daily habit and payroll is a monthly one, so the value shows up at month end when the two meet without a spreadsheet in between.
All plans
The register and the salary that both read it.
No — that is the point of setting them.
Yes, pro-rata pay is calculated against the days that were actually working days.
Yes, if the business changes which days it works.
Otherwise every closed day looks like somebody did not turn up.