Two things that are super confusing here;
First, you can have a rooster who is a prize winning Ameraucana, lets say a Blue Ameraucana, and he can mate with a prize winning Ameraucana hen, but of a different color variety, lets say she's Buff, the chicks that will be created from this match will be considered Easter Eggers because they will not be one of the eight accepted color varieties of the breed. They will be beautiful, wonderful chickens who have the muffs, beards, eye color, leg color and should lay blue eggs, but they would be disqualified if they were taken to a poultry show.
Second, in breeding for the Blue and Black color varieties, and in breeding for the Wheaten and Blue Wheaten color varieties, there is a color variety that is a natural by product, a small percentage of chicks will hatch out that are "splash" color. So their brothers and sisters may pop out prize winning Blues, Blacks, Wheaten, or Splash Wheaten, an these dear little ones pop out splash or splash wheaten - not accepted color varieties, so, once again, "technically" we are talking about EEers, though it is very common for these chickens to be referred to as Ameraucanas and it to be accepted. They can be used to breed and, with the proper mate, can produce some perfect Ameraucana of the accepted color varieties. So, not confusing at all, right.....