Yeah I don't think authority alone can do that. Authority, during the apostle training MC had, said something like "I speak and others obey". That implies that the 1st affects only people, minds, wills, or however you may put it. It only affects things that can decide their own actions.
A rock, meanwhile, cannot decide for itself anything, for it is mindless. No matter how much authority a king has, willing a rock to move won't do anything.
As for altering the rock's path, you are correct that you don't have to necessarily alter the laws of the universe to do that; after all, you can just alter its trajectory, weight, size, shape, and many other factors to achieve the same effect. However, "how the universe works" is rather obscure. Order would probably be able to just make physics go haywire (either in general or only for that rock) and make the rock end up where the user wants it to.