Prior to RO97009, TSSPC000 was only supposed to be called by CA Top Secret. The S0C4 abends and storage overlay only occur if a non CA Top Secret program attempts to use TSSPC000 and passes an invalid parameter list. The problem RO97009 was written for was found because the client has a product ZASSURE from KIR. Per KRI., they are basically doing FUZZING (or FUZZ testing).. which is a security scan methodology where in you invoke services with invalid data. The product scans the available PC's and then tries invoking them directly passing them parameters.
User applications usually don't do this.
After RO97009, TSSPC000 is no longer used by any CA Top Secret code or any other code. It was left in the product so clients would not have to IPL to get rid of it. It performs no functions except to return to the caller.