Unable to use "Use custom SQL"

Greetings,

I am a noob to BusinessObjects. We have Enterprise XI, Product: 12.1.0.

I have created a report and need to add a Case statement to the Report Objects. I also have a need to include nested queries (reports) etc. I was told that our company has turned off the ability for users to modify the SQL, and that it is an all or none function. Is this correct? Experience with other applications allow user roles to determine what level of access the users have. From what I have seen it is object based.

Would somebody mind explaining in layman's terms how the access control for items such as Use custom SQL is handled?

Thank You!