FBZ5 re-print check issue

Dear expert,

We have posted TT payment document in the system (F-53). Document number 1500000000/2013.

User accidentally re-print OLD check using FBZ5 to this payment document.

This cause a new check number has been assigned to this TT payment document (in check register program FCHN).

Actually we should not assigned check number to this TT payment.

1) Why re-print OLD Check FBZ5 will assign a new check number?

2) How to prevent check print/ assign to TT payment document? IN other word, How to allow FBZ5 for payment check only?

Appreciate your guidance.

Thanks