You try to use operation WGTYP then place logic and check whether it is working or not.
9501 -------> (There is no valid operation) message shows up.
ADDWT *
AMT-& 3046
ADDWT 3047
If it does not work you write PCY Z888 under > node but later remove your PIT Z888 from schema or comment it so that in Z777 conditions are met it loops to the Z888 then it works remember when we are using PCY GCY no need to insert it in schema with function PIT.
later PCR Z888 should be available in the system.
Regards
Venkatesh