If they are different sizes, then one's a Class V connector (2 5/8) and the other is Class III (2").
If they're the same, then like the others have said, either he doesn't like drop hitches or just wanted something like bike rack (or motorcycle) to be lower as those have ramps that need to reach the ground, have the proper angle for loading/unloading to clear the middle of the bike frame, etc.
I'm assuming that the lower one isn't properly mounted to the frame and can't handle much weight!
JMHO!
Bill
