I did not see this in person, so forgive me if I have any of the details wrong. As it was explained to me, in the power booster there is a plastic cup that the adjustable rod sets into. I was told the cup was cracked. When assembled with the adjustable rod and MC installed, when the brakes are depressed, the cup would split open and the rod would slip into the crack and not travel the proper and required distance. So this is why when we did all our measurements the rod length was proper, but when actually put to use, the rod was short. A replacement booster was installed and the car's brakes/stops correctly now.