To Mr. Jules,
During MCC you learn how to work in team doing lots of non-normal situations during the flights. So basically, it's just to check your abilities to solve problems using CRM rules. It's then 20 hours done in a Level C or D simulator spread into 10 h PF and 10 PNF.
The JOC (10h PF & 10 h PNF) is a tiny little bit different. You are doing standard flight to discover how line flying (in a jet) works. So basically, you can expect failures during the flight but it's mainly line flying in a jet. Therefore, you are required to use what you learnt during the MCC phase.
So to sum up: MCC = learn to use CRM & cope with non normal situations
JOC = use what you did in MCC to conduct a flight from A to B.
At least, that's what we did during my training.
Regards.