Twinkle's big city knits: Incredible Skirt/anyone make this?

Hi. Does anybody have this book? I must admit, I didn’t buy it coz the (junkie type) model really put me off but then I went & got it yesterday from the library. Thought I’d take a 2nd look & maybe make something BIG on big needles for a change.

I kind of like the incredible skirt page 128, short version. The needle size is weird: she doesn’t say when to change size but it’s in the chart I finally noticed. Then she says start with the largest, but in the chart it shows using size 17 for the first rows. (She has sizes 19, 17, 15 and 13 listed) hm. So what’s with the size 19 being listed?