Couple of clarifications.
1. A MOC can have up to 5 constituents at the academy WHO WERE CHARGED TO THAT MOC'S SLATE. In theory; the MOC could have 85 people from their district at the academy. 80 of them could have received their appointments from the "National Pool". THOSE APPOINTMENTS DO NOT go against the MOC's limit of 5.
2. Just because your representative or senator has 2 available slots, doesn't mean you have 2 nominations from him/her. If S/He has 2 slots, then S/He MUST SUBMIT 2 SEPARATE SLATES of names. When I look at one of my candidates, I see under NOMINATIONS that they have the same MOC's name 2 times. This means the MOC nominated him TWICE. Once on each slate. So, if you were only nominated once, then your odds didn't get any better. However; only having 9 on the slate instead of 10, does increase your odds by 10-11%.
But remember; those odds are for 1 APPOINTMENT. The remaining that were not selected, will go to the national pool. In there, there are no odds. Your chance of receiving an appointment is based totally on your total score vs the other 2000+ people in the pool.