One part says 18.2 and another labels it as 18.3 and your other mods that I have installed say that the 18.3 dependency version is not installed. I don't think I'm doing anything wrong.. I've been using mods for years and this is my first time seeing this.

Edit -- added this screenshot. See both "version" sections. I suspect the mismatch is the underlying problem.
https://i.imgur.com/1M4LIm1.jpg

The screenshot shows your current installed mod version is 0.18.2 (which requires base >= 0.18.7).
The left part of your "Install" tab shows what is the available newest version 0.18.3 (which should show requiring base >= 0.18.18).

It is my first time ever hearing people have this problem.
Maybe there are several things to check:
1/ Go "Manage" tab, see if this mod is using the newest version 0.18.3.
2/ If the version display is a selection box, instead of the plain text, then switch to 0.18.3. (It is possible that multiple versions of the same mod coexist in your drive, and you are/can use the older version.)
3/ If the above do not work, check the mod folder of your game installation (or whatever directory). See if file SchallTankPlatoon_0.18.3.zip exist.

Thanks for the fast reply, I didn't expect you to get back to me so quick! Ok, so looking further, you are right, it's all stuck on 0.18.2, I only see that vers. in my mod folder and it does in fact say 0.18.2 in my "manage" tab(https://i.imgur.com/0gdNKpB.jpg) ..despite no upgrade being available to me. I'm going to manually download and fix but I can't for the life of me understand how it got in this state. I'll update if I see anything further, my apologies for pointing the finger if it's indeed on my end.

Alright, the screenshot shows your game only finds the older version 0.18.2. Guess the in-game manage fails to download and place the new download there, or something like that.
Perhaps you need to find the mod folder of your game, and download 0.18.3 here and place it there. (As step 3 mentioned in above reply.)

Thanks, yeah I fixed it manually. After really drilling down I noticed that the entry for the mod was missing from my mod list json file.. so despite the mod being there, something happened where it dropped it on the floor for some reason. I don't think I could reproduce it again so probably not worth further time. Let's consider this an oddity but a closed issue.