A quote from developer George_:
"The manager is trying to keep maximum number of allowed corpses in the scene. It works the way that the oldest corpse is removed from the scene if the current number of copses is bigger than corpseLimit but only if the oldest corpse is in the scene longer than corpseRemovalMinTime. It also removes corpses that are longer than corpseRemovalMaxTime (default is 1 hour).
The manager is used only for units that are respawned by in-game mechanic (AI in player slots and players, it's not used for units generated by scripts). We can expand the system for AI if you find it useful (but thats probably for another ticket :)"
So as it currently stands, the system only works with playable units.
My proposal is to provide mission makers more control over this system. The ability to add and remove units to/from the system via scripting commands would provide total control.
An optional parameter in description.ext for the system to blanket cover ai units would also provide us with more control.