Explanation
The purpose of 00 to ZZ is if the user needs to view all the data from for that input criteria combination.
For eg In invoice report the Criteria to generate reports are Site Code, Invoice Id from and Invoice Id To.
1) Site Code will be Default as User login site.
2) Invoice Id from and To combination gives the option to view only single invoice, multiple or all invoice pretaining to that Site
Suggestion
It is recommended to enter specific values or range of values if available with the user.