The coral reef and reef fish biologists at UNCW both mispronounce acropora and montipora (so do I for that matter). It really doesn't matter as long as the other person knows what you are talking about.
IME with zoos they are pretty dormant when you first add tehm to the tank. Then about 3 or 4 months later they begin to spread. Some slowly, some fast. You can try to target feed them with some cyclopeze or crushed flake food to encourage them to spread. Be very sparing on the target feeding though.