So I finely got the shadow chamber in my game. I've noticed that it doesn't really give any information anymore which makes me said. However, when it came to the site that the codex gives you, the shadow chamber actually shows all the information. Types of aliens, number of aliens. Upon reviewing the forums, I saw that there was a "dynamic" issue to showing the numbers.
Now the TacticalUI KillCounter mod shows the total on the map. So it seems to me that it should be possible to use the shadow chamber to run the final numbers? Perhaps on the loading screen? Just so you know what to expect? If you are using this mod and don't want to know the numbers, there is a setting in the mod to turn it off.