Approval processes does not stop with approver

Dear All

I have an issue with the PO Approval processes.  The approver Mr.X has a limit of 30,000 but the PO for a value of 25,000 does not get into Approved status even after Mr.X approves it; instead, it goes furhter in the line, and goes for the approval for Mr.Y, the boss of Mr.X.

I have checked the approval assignments and approval groups.  All seem to be fine.  I ran the script providved by oracle to reset the PO into Incomplete status, and tried approvals again.  But it does not work. 

Please somebody given me an answer for this.