Augmented is odd. It's default in that anything that changes your type that isn't some form of shape-changing (so mostly just templates and capstones) says you become an X (Augmented Y), where X is the new type and Y is the old type.

However, there's no rule that actually mandates that that happens.

Also, it really wouldn't help most characters to be pure Outsiders instead of Augmented, because most characters are from 1 or 0 RHD races, so they don't have any RHD to change from their old type to the new one.

For the few with RHD that are still playable and worth playing, it'd just be really annoying to recalculate, especially since it could change your skill points and hit dice, which would be a bit of a problem since they're not supposed to change retroactively.