Sushni:
Those parameters restrict which IDs the owner / controller can SUBMIT request for, not the approval.
As the functionality is designed, when you have a FFID in the systems, and UserA is the owner and/or the controller, the system should NOT allow assignment of that FFID to UserA as he/she would be the one to approve assignment or approve the log workflow.
You should not have to make sure that users don't use FFIDs they are owners or controllers of as the system is designed to disallow that situation.
Unless I am missing some information, this is how I have understood EAM is working and has worked for quite a while.
Thanks,
Kevin Tucholke
Principal Consultant
SAP America