So the guys at PRO just told me that any customer who bought a Atlas arm who in the future wishes to upgrade to the Titan arm when they have the money can just return the Atlas arm to PRO for a $ credit toward the purchase of a Titan arm. The dollar amount depends on the condition of the returned arm, but this eliminates the hassle and time of trying to sell your used Atlas arm on the forum when trying to upgrade.
Wow! What a deal for the guys just getting started in this craft! I wish these deals were around when I got started.