Hello Srinivas,
The suggested fms to be used in the include ZXWOCU07 of user-exit IWO10009. After this according to your code the changes would take place in these operations when the Order is saved (IW32 or otherwise).
BAdi (WORKPRDER_UPDATE) also can be opted in place of user-exit IWO10009.
Regards
KJogeswaraRao