Wow, um this is kindof an old problem so there may be a patch. I was using the zombie mod one day and I noticed that the zombies I killed were respawning right after. I looked into my add ons and didnt see any conflicting add ons. This started just after I got Teir+Tactical, but I think bushi would have noticed by now.
Example: I come across a tank, standing on its spawn, then I kill it in a heated battle, I think for a second, Im safe :D! But then the tank respawns and kills me. Or a fast zombie, I will be standing infront of the spawn, firing a turret or smg and the zombie respawns RIGHT after, I can get hundreds of points from zombie spawn killing.
I cant really explain this, I mihgt post a video later.