You're missing the difference. GL has every dimension be a Brane membrane/bulk space. Which means that each of them are embedded in that larger space. A standard bulk space under M-theory is a 4th Dimensional construct with string dimensional of finite size that loops around them at higher dimensional
angles like in this image. Just mentioning bulk space isn't enough for High 1-C or 1-B, you'd have to show that every dimension acts as a brane layer or that every higher dimension is infinite in size by embedding the other. I'm not seeing either here.
Pan-Dimensional doesn't mean anything, as String Dimensions do operate at higher levels and they're just finite in size. Its why being 11th Dimensional isn't a High 1-C showing. You have to affect something is significant size, which is why Neptunia has that rating because the cosmology they effect under the coordinate space assumption qualifies for 1-C.
I think Low 1-C is fine, I don't see any higher rating here. It lacks more fundamental elements required for it in my view.