Hi Dushyant,
Are you using rounding rules for currencies in IS-U.
Rounding rules ensures that the amounts that result take into consideration the currency unit specified, provided it is also considered when amounts are entered manually.
The payment program analyzes these specifications for determining the cash discount and rounds the amount according to your entries
Check the config SPRO-->Contract A/C AR &AP-->Basic Functions-->Postings and Documents-->Define Rounding Rules for Currencies
Also check posting areas 0040 and R402.
Hope it helps...
Thanks,
Amlan