[Mike C]

Actually, the keys can crank it a LOT higher than just the bolts. Because they re-index the torsion bar relative to the frame. The idea is that it lifts the truck while keeping the load bolt in the lower part of it's travel so you can use it to level rather than having it cranked all the way in. So if you crank the bolt up and you have the lift keys, you can get all of the front end parts out of the sweet spot where they work without excessive wear and binding.

If you work the truck hard (pulling, mudding, bouncing, etc.) you can cause the half shafts to overextend as well if it's cranked too much. Once again why 4" lifts and more lower the differential and the torsion bar mounts.

One of the reasons some people have problems and others don't is it depends on which key was in the truck originally. Cranking the bolt all the way up on some raises it more than others.