The moorings are designed for a specific size (determines how far apart they are set) and boat weight. This theoretical maximum weight is computed with the expected forces during a storm to calculate the type of mooring, and how big and deep it is set. The force generate by backing down with 1500RPM for a short time is going to be far less than the maximum expected mooring capacity. FAR less. Backing down doesn't check the mooring base, it checks to see if the lines are still solid; often in the BVI I've seen 2 out of 3 strands of a mooring line chewed away by the props of some other boat.

Reference: Principles of Yacht Design