the queens don't respawn until the NPC count reaches 0, how do you fix a timer to that?

Queens will spawn multiple times. Not when the mission ends.

Starblaz that is incorrect.

yeah i too feel like the queens respawn multiple times, havent been to a levi sector in awhile. ill check that...

After 100+ Levi kills I can 100% tell you they don't respawn before the mission ends.