They aren't different types. There are 3 different ways the MOC can present the list of 10 nominees to the academy.
1. Competitive list. They simply send their list of 10 nominees to the academy and tells the academy to pick one and give them the appointment. This is how the majority of MOC do it. The academy usually gives the appointment to the individual with the highest score on their application.
2. The MOC can rank their list of 10 nominees. They write their #1-#10 choice and assuming the individual(s) are qualified, the academy MUST give the appointment to the #1 listed person. If they aren't qualified, the academy goes to #2 and works their way down the list. This is called a Prinicple nomination. And the other 9 are simply ranked.
3. This is a combination of the first 2. The MOC lists their #1 ranked nominee and and the other 9 are competitively listed. If the #1 is qualified, the academy must give them the appointment. If they aren't qualified, the academy can choose any of the remaining 9, similar to the first method above.
And remember, only about half the appointments are using a MOC slate. All appointees must have a nomination, but only half are filling a MOC slot. After the MOC appointees are done, all the no appointees, the other 9 from each MOC list, are put into a national list of about 2000 and the academy pickles the remainder of the appointments that they need to fill the class from this national pool. Minus a few others that they got from other nominations like presidential, Rotc, and other military related nominations.