Not necessarily - USAFA knows it's historic yield rate (the percentage of offers that get accepted) and builds this into their process. There may be some late offers generated if the class size is looking smaller than their goal for the Class of 2023, but I would not assume that a "decline" automatically generates an additional offer of appointment at this point in time.
If it's from a MOC's slate, would that slot then get pushed into 2024, or would it go to the alternate or next qualified?
Typically, it will go to the next qualified on their slate that has yet to be charged.
~ IE if the candidate is sitting in the pool.
This is why USAFA will say you are still in the running until you get the TWE.
They normally will not push it to 2024. The only way that I know of the slot being pushed to 2024 is if the candidate goes to BCT, and is medically turned back, or opt to quit BCT. The MoC would be informed that they now have 1 more slot available for 2024.
I have said this many times. Think of the appointment class like a 1350 piece jigsaw puzzle with no idea what the picture will look like in the end.
~ Principal & LoA w/noms that are 3Q are the outside pieces. Easiest to place
~ Multiple noms, 3 Q are like the pieces where you can easily see that it fits, but you may have to try all 4 sides.
~ Single nom. 3Q, it gets harder, because only 1 or 2 sides will fit (MoC charge or pool)
~ National Pool (Moc has been charged) 3Q, and the above candidates with a DQ (LOA/principal) waiting on a waiver are the last pieces you place.
This is why it takes so long. They have to keep figuring out where that piece goes.