Sounds more feasible than my idea of how things worked. I don't know where you get all this information.Wildly off the mark as far as I know.
I've worked with a 4SAR who I know to be in the main merit table with other dual/SAR level 4s.
So you have to outperform all level 4s to get out onto National League
The merit table is also used to determine if a reclassified level 4 can be offered 4SAR (have to be in top 30%)