Difference between Form Function FND_FNDRSSET_USER and FND_FNDRSSET_SYS

There are 2 Form Functions named FND_FNDRSSET_USER & FND_FNDRSSET_SYS which invoke the "Request Sets setup" form.

Internally they both call the same form FNDRSSET but differ in the value of the Mode parameter passed

i.e.  MODE="USER" & MODE="SYS"

I could not find any documentation which lists the difference between the 2 calls.

i.e. how does the functionality differ in the form depending on the mode values passed ?

Any input would be appreciated.