I believe the cleats are fine for Mooring. There have been boats damaged after running aground when attempting to drag the boat off using the crossbeam cleats. Leopard does in fact however recommend they not be used for Mooring. I usually run each line from the bow side cleat to the ball and back to the crossbar cleat. Now you have 4 cleats sharing the load.
The worst possible way to moor a cat is a single line from one side of the boat through the Mooring loop and over to the other side. I see this all the time.
G