Now that I've gotten the bulks pulled off, I can see why the bottom pin has to be longer. They changed the design so that the lower A arm is fully "captured" by the bulk. Stock, the rear of the front lwr arm has the pin/eclip against the plastic arm - FLM hybrid extends the alum so that the rear of the arm is no longer "exposed" and the pin/eclip is against alum on both sides of the lwr arm.

They did same in the rear, except the added alum is toward the front of teh rear bulk since thats where the a arm was exposed. This is a stronger design as far as the lwr hinge pin is concerned since its now supported by the bulk on both ends.