It should also work if you would use
ZL03 Late Attendance Cumulate Gross WTs
*
****
VWTCL 91 Processing class
*
ADDWT * OT Output table
1
ADDWT 1234 OT Output table
ADDWT * OT Output table
The problem with your initial attempt was that any WT that didn't have Pr.Cl. 91 with value 1 would have given an ERROR (and stopped Payroll Processing).