It doesn't matter and I would advise that you don't pay any attention to them unless you do everything else that they do as well. For example, if somebody is thinking about using Jason Fox's parameters and stuff, then are they going to change massive amounts of water too? Picking and choosing parts of an overall system is not good. Besides, what makes any of you think that they have optimal water parameters? There is so much happening in some of those systems, that they some never are very stable... some of them just get by on turning and burning corals so fast that they don't sit around long enough to get stressed. Their models are different than ours.
You are far better off following along with what some high end hobbyists do for what you are trying to keep. No needed in trying to keep acropora water for Z&P, so find some high end Z&P tanks... or whatever.