It sounds like the test was done in a fair way. Each of the 4 parks had one morning EMH and one evening EMH. If they stick to this, at least everyone will have one type of EMH that they like (of course, depending on the days of your stay). Once they announce a schedule, it will be easier to plan.
By the way, both morning and evening EMH will be available for guests at Disney operated hotels, The Swan & Dolphin, Shades of Green, and Lake Buena Vista Hilton.
Mike