Sewing project progress: full gathered skirt in red dupioni, part III

Well, I screwed up. I just discovered my first noticeable mistake in my skirt making.

Where last we left off I was struggling to understand how the waistband met up with the body of the skirt, and I thought I had figured it out thanks to a comment from wired_lizard* about how it's supposed to be flipped over to hide the attachment seam. So I pinned it together in a way I thought was proper and backstitched it together. But when I flipped the waistband over that new seam, I got this.

This is supposed to be the right side of the skirt, the outer side that is visible, and you can see the seam holding the two sides of the waistband together. That's not right. I am certain the problem came from attaching the skirt to the incorrect side of the waistband, but I'm not sure where it was supposed to go. Again, my directions were "Next, you're going to pin the interfaced side of the waistband to the gathered skirt, right sides together. Find the middle of the waistband by folding it in half. Mark that point with a pin. Match the halfway point on the waistband to the side seam on your skirt. Next, pin the ends of the skirt piece to the end of the waistband. The finished ends of the waistband will match up to the raw edges of your skirt." Gertie then specifically notes to make sure to pin the skirt only to the interfaced side.

I'm not sure where I went wrong. My gut reaction is that that what I did would have worked out if I hadn't turned the waistband right side out, so that when I flipped it down now that seam would be hidden, but Gertie specifically has you do that. So what wasn't lined up properly? I kind of want to make a paper model and see what the physics of it actually are.

Ah, well. It's easy enough to fix. What I'll have to do is fold down that seam along the top and sew it onto the inside of the skirt with an invisible stitch, as well as fold up the loose bottom edge of the waistband up inside itself, and sew them both with an invisible stitch. Here is the inside of the skirt, with that top seam folded back and pinned down. Note that the interfacing is visible from the inside; is that correct, or should the silk side of that piece be exposed?

And here is the outside view, now with the bottom of the waistband rolled up and pinned as well. Both of these I will attempt to use the blind stitch to finish, as it is supposed to be invisible.

So can anybody tell me where I went wrong? I'll let you know if making the paper model illuminates anything...