Extra MCC hours aren't very useful beyond what the syllabus provides because what value would those extra hours have?? MCC isn't about type specific handling, it's about teaching MCC and very basic CRM principles. I seem to remember during my MCC training that the instructors didn't even care about your flying as such, just the way you went about operating the machine. Besides alot of MCC training is provided using simulators only at or above FNPTII quality, so any handling is only 'similar' to the type it's trying to simulate. Regarding a certain spanish based UK FTO's simulator, the real A/C type has rear mounted engines, but the sim model is set for underslung engines!
A company specific JOC is more useful for learning SOP's, but doing extra MCC work off your own back is probably just a waste of cash.
My two pennies anyway!
Atreyu