There are entire threads on this, but the short answer, is the shape is to cover the rear A/C lines for cars so equipped. With that size, you should have no rubbing in the front in any condition, and you will have rubbing in the back on the bump in the place you mentioned, but only in an off-road "stuff" situation, or driving in access and hitting a bump. You could get the rub if you make a pretty fast turn from low speed as the body shifts before DSC catches on. Under extreme use, the area will eventually wear, and it may end up with a small area worn through, but do not fear, as the panel is meant to hide, and not necessarily waterproof, as it all drains out of the bottom anyway.
How can you avoid all of this? 1. don't do the tires, not the best option. 2. I suppose you could try to rengineer the panel. Frankly, I'd mount them and let it go. After 18K milles, I stil have at leat 1/2 the tread left, and I use the tires what they were made for.
My $.02