I would be more inclined to say you cupping issue is related to your tire rotation. Do you have mt tires and how often do you rotate them? Mt tires will wear like that on the front outside edges if you don't rotate often. 3-5000 miles is all I can go, I start noticing the outside edge wear before 5000 mules but it isn't bad at that point.

This happened with my stock shocks and teraflex shocks.