Someone posted that a young man received an LOA during NASS. The admissions board doesn't issue LOAs. After the newly assembled class is sworn in is when the admissions team gets a break. They switch around spots, the LTs PCS and the new folks come in, etc. Its when they take their leave and vacation with their families. They are catching up in the office and taking a collective breath after a very busy year. The admissions process is very cyclic and they know where their break points are to take their leave. Once they all get settled back in and start reviewing applications, LOAs will start to roll out.
Remember LOAs are the exception, not the rule. When this board lights up with them some folks will start to panic. It will seem like tons of people got them. USNA doesn't publish how many they release. Some speculate it's around 150-200, none of us know for sure. I think on the 2020 appointed thread this year is was around 10-15% or so with them. There was one young man who posted who had an LOA and no Nom. He never posted back if he was given a VP nom or got off the NWL. A few BGOs on this board have stated this happen to candidate, it is rare, but not unheard of. Focus on what you can, an LOA is nice, but not the goal. Ask any 2020 Mid right now what an LOA has done for them right now or if anyone cares at this point.