ZUIM transaction code to report the users hving write access to the system

Hi Guru's

I am facing the below problem.

We have developed ZUIM transaction code, where in we get a report of the users having write access to the system.

But this report also includes certain users, but wherein actually these users dont have access to XK01 transaction.

If tran. SUIM (standard SAP Transaction) is showing that XK01 is not accessible to a particular user id but yet tran. ZUIM is listing it as available,

I ran tran. ZUIM for transaction XK01 and it did list 'X'user as having access to XK01 but if I ran the report just for user 'X', I cannot find XK01 on the list of transaction that user 'X' can execute.

Please help me.