It's not the pin in the spring pack that's the issue. The issue is when you do not have weight in the truck the springs really push the truck up (over 4") and as the spring pack arcs up the rear axel moves forward as the shackles swing forward. This bottomed out the rear DS on my truck so I chose to move the axel back 1" to center it better in the wheel well and gained slip back in my DS. Now as the springs compress and the shackles move rearward the axel will move in relation to this arc but I do not think there will be enough compression before the tires hit that the 1" will matter. Now if your asking why they did not move the pin in the spring pack back to compensate, ? I guess it could be a item to consider in the design. It's almost as easy to use relo blocks or drill the spring perches to compensate, same issue comes up in SOA's