Need advice on what formulas to use for calculating work times at different
overtime rates, all on the same weekly time sheet

IE: Ordinary time 7hrs. (First hr of O/T X 1.5) subsequent hours X 2 (Mon-Fri)
Saturdays - 5hrs X Ord.Time - 6th hour X 1.5 - subsequent hours X 2
Sundays - All hours X 3
Public Holidays - All hours X 3 ( here we need a PubHol identifier,as
well)

End result should be total payable hours at a base rate