CBAC - inherit privileges through role not working

Not sure if this is the right category, but I think I should find people experienced with CBAC here. I am studying documentation and play with some features. Right now I have an invoker's rights procedure and to secure the invoker, I revoked the INHERIT PRIVILEGES privilege that was granted by default to PUBLIC (as described here). Then I want to allow only a particular owner to inherit invoker's privileges. If I grant him directly the INHERIT PRIVILEGES privilege on the invoker user, it all works good. However, I came across this statement here:

As an alternative to granting the INHERIT PRIVILEGES privilege to the procedure's owner, you can grant the privilege to a role that is in turn granted to the procedure.