Question about moving screens

[81artmonk]

Have a two part question. I will see if I can describe it well enough.
Player A1 has the ball and is moving forward.
PLayer B1 is in front of A1 defending back pedaling with the ball.
Player A2 is behind B1. also back pedaling. Player A2 is not in a screening position. Imagine a straight line A1 than B1 than A2
A2 gets called for a moving screen.

A2 gets called for a moving screen. Two part question.
If you are not in a screening position can you get called for a moving screen. And two, can you get called for a moving screen FAR from the ball. Let's say the ball is front court and Player 1 commits a moving screen on a defender in the backcourt under the basket 50-60 ft away from the ball and the play, is that still a moving screen. My limited knowledge is that the screen has to be in the area near the ball handler in order for it to be a moving sceen violation. If you are away from the ball, how can it be a moving screen as you are not screening the defender from anything especially the ball??
I was told by the refs that you do not have to be in a screening postition in order for it be a moving screen, to which I asked how can it be a moving sceen if the player isn't screening anything??