I made another modification to the robotic arm. First, to make sure a jack will trigger the lever switch, I covered the end of the arm with neoprene foam. That makes it more likely the robot will detect jacks when they are picked up off-center.
I saw a problem were the arm successfully picked up a jack, but then dropped it after rasing the arm. I'm going to need to add a line of code to the robot to check the switch at the end of the arm one more time after the arm is brought up. I only have three bytes of memory left, I hope I can shoehorn that in.