Just because you have a nom it does not mean you will be charged to that MoC. The SAs know from historical data where the definitely will be appointed (WCS score) lands. Thus, they can be appointed, but not yet charged to the MoC. Basically if they don't win the MoC slate they are going to come out of the national pool.
~ Just bc someone posts on the appointment thread MoC (SEN or Cong) don't assume that this is fact, unless they were principal. Look at an LOA for example, they just need the nom., but an MoC can give them a nom., and also a principal. The principal will be charged to the MoC, the LOA will not be charged to the MoC.
There are appointees with multiple noms. The 1st may come in a few weeks prior to the other noms. They could all be competitive. They get an appointment between these few weeks, thus, they assume it is from the 1st nom due to the fact the other noms were not listed on their portal. However, nobody can be charged (except principal) until all nominees have been boarded. If the slate has 10, and only 7 have been boarded when they get the BFE, they are not officially charged to the MoC. They just assume that they are. Feb 28th rules around, everyone has a WCS. That appointee with multiple noms thinking they were charged to that 1st nom., could actually be charged to the last MoC nomination.
It is not uncommon for competitive areas to have 8 or more on the MoC slate to get an appointment. Use Sen A as an example
Candidate 1: Pres, VP, 3 MoCs. Charged to Pres
Candidate 2: 2 MoCs (Sen A and Cong district 1) Charged to Cong
Candidate 3: 3 MoCs. Charged to Sen B
Candidate 4: 2 MoCs (Sen A Cong district 2) charged to Cong
Candidate 5 : Sen A only, but with an LOA, charged to Supe
Candidate 6: Sen A only, and ROTC nom, charged to ROTC
Candidate 7: Sen A and VP high WCS charged to VP
Candidate 8: 2 MoCs. Sen A and Cong district 3. Charged to Cong district 3
Candidate 9: 2 MoCs, Sen A and Cong district 4 . Charged to Cong district 4.
Candidate 10: Sen A only. Charged to Sen A.
Yes, the highest WCS wins the appointment on the slate, but look at appointments like a 1300+ jigsaw puzzle. Candidate 10 may have actually been on the lower end of the WCS on the slate, however, bc the other 9 candidates were able to be charged differently they are now charged to that Sen since in the end they were the highest WCS left when it came to charging.
Hope that helps understanding how someone or many someones on an MoC slate may post that they have an appointment before mass mailing March.