What if you were to switch to a one size larger needle for the ribbing? It wouldn't be detectable, but would make the ribbing slightly larger around, and less likely to crawl up your hips to create the bunching bulge thing. Do you think so?
The ribbing would skim your hips
instead of hugging the hips, and not be as prone to crawl.
Just a thought.
I did this with a top-down cami-tank
last year. As I worked my way to the waist and over the hips, I didn't want to make increases in the st st...I just increased the needle size (twice in fact) to make the ribbing begin to flare out to go over the hips a bit. This was my own design, so I was tinkering with all sorts of options. It was knit 'in the round'.
Here it is: