I think Diana is right. In the photo, it looks as if they might have the line a bit higher than the model's waist. But the waist measurement is for natural waist (actual waist). And your hips supposedly match up with that, ha!
When I was more of a pear, I used to buy my jeans by HIP size, not waist size. I pretty much always had to wear a belt.
Now my waist-hip ratio is closer to what these charts seem to expect, although my hips are on the narrower side. So I buy with the waist measurement, knowing the hip will fit me.