I’ve changed my mind after seeing this from Troy back in 2011.
No such thing as a roaming 180, and if some state match or other called it that, they were wrong.
The 180 can be shifted to be parallel to the back of the course of fire, especially if the stage is set into the corner and designed to be shot "diagonally", but just because you have a corner there doesn't mean it moves. The way that stage is laid out, the 180 is parallel to the backstop.
Troy