I almost feel like this should be an example for the floor of the plump tag. Any more body fat than this should warrant plump I think.
But I don't really know what our standard is for said tag to begin with. So maybe not.
There isn't really a defined or followed standard for the tag. Part of that problem is that most people uploading from Pixiv seem to click the plump tag on upload just because it's being translated from Pixiv's equivalent, and not checking if it actually fits the post (it often doesn't, at all). Then others get the wrong idea from seeing that.
Anyway, I didn't think this was quite enough for a tag that says "plump", so I left it off. But I do agree with this being the "floor of the plump tag".