No Idea. The RDLogics CVDS and the Dynamite CVDS have slightly shorter bones and longer drivecups than the MIP or UE. My guess is they are using the same drive cup as the XTM or Dynamite so they chose to use it with their own dogbone (RD dogbone is quite beefy vs. the Dynamite or XTM). Probably to get the price lower. The RDLocics CVDS are a great bargain, but can't be used with 1/8 diffs.