Yeah. So if a pipe that carries a low amount of water ends in a pipe that can carry a large amount of water, the next pipe simply carries all the water and its exact limit doesn't matter.

However, if a pipe that carries a large amount of water ends in a pipe that can carry only a small amount of water, the next pipe can only carry the amount of water it can hold.

The rest of the pipes matter, because some limit the amount of water that can fit through them. Yes, the last one of 74 doesn't matter, but it's a great way to mess with people, right?