There are significant differences between stock ball joints and Dynatrac Ball joints.
The lower stock ball joint can pivot. The upper stock ball joint can only slide in and out. The lower Dynatrac ball joint will pivot. The upper Dynatrac ball will slide in and out AND pivot.
When we reseached the JK for the Dynatrac ball joints, we found that factory 'Cs' were bent in various directions. The upper factory joint was getting sideloaded (due to bent 'C's) so bad that it caused early ball joint failure. By allowing the upper ball joint to pivot slightly, it allows the joints to stay parallel without sideloading the ball joint.