Hate to say, Olive Eggers ARE Easter Eggers. They are a cross who's intended to lay a specific color of egg... they're just named for the color of the egg. Because their a cross, like EE, there is a certain percentage of chicks that won't lay true olive colors. The further you get from the original cross, the more that percentage goes up.
Right now we're in the age of designer 'breeds', from designer breed dogs (like the puggle and chweenie and labradoodle) to designer chicken breeds (like sapphire olive egger, prairie blue bell egger, etc). They're all just crosses and not true breeds.