Hunting marks possible Spawning rules

This rules are base on my experiences, and its just a conjecture base on my observation, so far it works for me.

1. maximum number of marks in all map.
-Assume the server only allow 3 marks up at the same time, you need to kill one of the marks exist to spawn another one.
2. Individual CD on each marks.
-B should be 30 min, A should be 3-4 hrs, S depends on condition and have more than 24hrs CD
3. Even the marks already finish CD and ready to respawn, they will not respawn immediately. They will be put into a Queue and waiting for spawn following the rule #1

Why I assume that:
I was hunting few weeks ago with only teams in my LS and share info with each other, even we can not say we kill all the rank B at the time, but all the rank A are recorded and on tracked. At the time, there way at least 5 A ranks up, but no one can find any of em. Somehow, after we kill a B rank in a no-A-open map, the A ranks spawn one by one.