I actually don't think they will.
Capacity guidelines were very low when the Boo Bash tickets went on sale, then capacity mandated numbers were increased a few weeks later. It also was probably that at the same time Florida's C19 numbers were climbing steadily so there were a lot of cancelations being discussed and folks rescheduling. But once that passed and tickets started selling out they didn't do another round of 'extra' tickets.
Since then, there hasn't been any additional talk of large increases in capacity mandates.
It feels like maybe they started out with the availability for Merriest with the numbers they eventually ended up with for Boo Bash, and are not hitting those sell out dates as fast. (again maybe C19 but also probably just the price structure)
But with Disney who knows. Profit always wins out.