MyBB Community Forums

While playing with MyBB on a test forum on localhost, I noticed that mods inherit mod permissions for subforums. (For example, mod A of forum B will also get mod perms for B's subforum C even if I don't specifically add A as a mod to subforum C.) Is there a simple way to disable that so that they don't?

I think I resolved this by editing forumdisplay.php, functions.php, inc/class_datacache.php, and inc/functions_forumlist.php.

Are there any other files which I should be aware of which look at moderator permissions which may need editing?