Blueworx Voice Response does not automatically check mailbox definitions: only the messaging application can check to make sure mailboxes are being used properly. Therefore, the application designer must tell you what information is necessary.
The application designer can interpret the system variables in any way that is appropriate. For example, value 0 for the Caller : Mailbox : Access mode system variable (SV106) is documented as meaning “Global”, but your application may use it to mean “Read-only”. To make it easier to use such Mailbox Options in the Application Profile window, you could edit the display text in the language database (see the Blueworx Voice Response for AIX: Configuring the System information for details).