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An Use Supplementary Rate for Oncost Calculation field has been added from the 11.37 this release on, to individual oncost rates that belong to a pay or bill oncost that is configured in Rates and Rule Maintenance. When ticked, the Use Supplementary Rate for Oncost Calculation field enables the supplementary oncost rate method of calculating the oncost rate, whereby the pay rate of the pay items that was paid is substituted with that of another pay item in the oncost calculation (for more information, see Supplementary Pay Codes for Oncost Calculations).
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