Limit File size in mAddAttachment in PT 8.55.04

We want to limit attachment size on Voucher component. I am trying to make this change in Finance 9.2/8.55.04. it does work when I hard code the value but it does not when I read from message catalog or url definitions. For some reason it does not like it when the value is converted from string to number and then passed to the function. I get invalid parameter type passed to the function when click on Add Attachment button on the voucher component.

This works:

Local number &COF_MAX_FILE_SIZE = 0;

   If %Component = "VCHR_EXPRESS" Then  

      &COF_MAX_FILE_SIZE = 1050;

   End-If;