I was on a limited device earlier which created a less than helpful post.
I just did a clean test on Altis, no mods except ALiVE. I put in the required modules plus civilian population and civilian placement. The parameters were default (no filtering both) except for placement level, which was set to extreme. No TOAR was defined.
The results were some major settlements were not recognized by placement module. According to the debug info on the map, the settlement just wasn't recognized. For a quick example, there is a settlement near the ruined castle named Oreokastro that is not recognized. Its a fairly sizable place.
Obviously when I run Takistan(CUP), I am using mods. In that case, I tested a great many parameters. I tested default tests, where I ran module defaults. I ran different TOARs and no TOARS. I didn't mess with the filters much, because I was not seeing settlements populated in the first place ;-)
In Takistan, it did recognize all the settlements that I checked. However, as I stated, it wasn't consistent with how it spawned civilians. It did spawn ambient vehicles without problems, though.
To be very specific on Takistan- I setup a civilian population and a placement module, the placement didn't have a TOAR. I went with default setting first and noticed many settlements were not populated at all. Some were and some weren't. The fairly large settlement near the airbase was barren, though the module detected it. It did populate the smaller settlements on either side of the deserted one, though.
This is where I started running various tests to figure out the problem. I then setup the placement module with a TOAR that encompassed a few settlements near the airbase (including the one that didn't spawn anything) and that was it. The result was that it perfectly spawned civilians in all the settlements within the TOAR.
So, then I added another TOAR to the module, one that included a few more settlements- it still worked perfectly. BUT the more settlements that I added to a TOAR, the more sparse all of them became. It reached a point when I covered half the settlements on the map with a TOAR and then the massive gaps began to appear in the TOARs (the same gaps that appeared in the no TOAR test).
This is what lead me to the conclusion that the civilian placement module reaches a saturation point where gaps begin to appear in the settlements, both in density and in location. Having said that, Altis seemed to handle the civilian modules much better.