Time and Pay Calculation was enhanced to support pay or compensation changes part way through a pay-cycle, considering for hourly compensation types the actual number of payable hours recorded up to and after the valid from date of a mid-cycle pay change. Only one mid-cycle pay adjustment is supported. In addition retro pay was refactored and completed. Retro-pay deals with the impact of making retrospective compensation changes which need to be applied to closed pay periods. When the retro-pay option is enabled by entering a date in “Process retro-pay changes from” pay is recalculated for all periods from this date and compared to employee payroll data. Any differences are added as retro-pay using retro-pay earnings codes in the current pay period. In background mode retro-pay calculations are triggered if compensation rates are changed for previously closed pay periods