Cupping is common from improperly balanced tores. Specially common with tire/wheel combos from small dealers that don't have the proper balancing equipment.
I always use either the Jeep dealer or a specialized name brand tire company for my balances.
A realy good original balance and rotated tires should last the lifetime of the tire.
Cupping from alignment can occur from axles way out of alignment.
It does take a while for the computer to reset itself.. Sometimes a month or more.
Big JIm <img src="/forums/images/graemlins/pfft.gif" alt="" />

professional bovine relocation specialist