Dear Woody,
Thanks for your reply and good documents, actually SAP has provided standard solution to handle sick leave for one service year, you just need to have some configuration , and it works perfect.
function XNAB in payroll schema is responsible to apply valuation rule for each day of a sick leave.
if the sick leave still within 30 days in a service year, XNAB will put 05 Valuation Rule (meaning its fully paid), if sick leave already gone beyond 30 days, XNAB will put 06 for that day sick leave (meaning 75% paid)
it works perfect.
when retro runs for Feb/2013 again, XNAB should count the sick leave till Feb only for that service year. but its counting the sick leave from future dates also....which is wrong. by this way XNAB is putting 06 valuation rule for Feb sick leave, which was 05 in original payroll run.
there is some problem in XNAB function.