I guess your sort control cards (INREC IFTHEN..) in SYSIN DD * is starting from Position 1. It should be from Position 2. Show us your complete JCL what you have tried...
also would like to know the significance of "PUSH" field as why (81:ID=4) mentioned.
Here PUSH is used to define the input field, sequence number, or identifier that will be overlaid for each group’s records.
ID=n Specifies a printable Zoned Decimal (ZD) identifier n bytes long, which will be added to every record of each group.
For the first group,the identifier will start at 1 and for each subsequent group it will be increased by 1. The number n can be from 1 to 15.