[AtlUmpSteve]

The only thing I can add is one way to try to avoid the confrontation.

Have the catcher answer him, instead of you addressing him directly. If the catcher says "They are high", or "It was too high", or even their version "Deep", there is a better chance he accept it and try to adjust. So, tell the catcher what you are calling, let him answer. Even if the catcher doesn't agree, it sounds like he is buying in.

There is a possible downside, however. When the catcher says "HE says they are high", the catcher is telling the pitcher he agrees with the pitcher, and not you. In that case, either they don't know, or your zone is off; and you may end up having to toss both.