First of all, and welcome to the XMTS DIY club, and for including a photo with your first post!

I think that observation can clear up lots of confusion. My suggestion to you is to go to a shop that sells kilts and try one on. It doesn't matter whether they're traditional tartans or casuals, like Utilikilts®. While you're in the dressing room, look carefully at the construction, especially what's happening with that deep pleat. I'm sure that it will all make a lot more sense after that.

If there's no kiltseller around, maybe someone in your community has a kilt that you can look at. Best wishes!