I don't know if this is going to answer your question at all, because though I have CF, I'm not sure how exactly the numbers work with it, but I do know that I do not have one of the common ones, I believe the most common is delta 508, I think, but I do have a rare kind of CF myself. It's not too different but if you need someone to talk to who does have 'their own kind' of CF I'd be happy to talk with you!
Good Luck!
-Alex