I'm not sure if you really wanted your question answered but the reason they can offer it for so much less is because there in no middle man mark-up on the price. Factory direct basically. If you have not heard of www.svsubwoofers.com you should check them out too.
FWIW i was able to purchase a P2000 for $1100 shipped, or ~ $150 more than the 950. It was worth the difference to me for the faceplate. If any of the other improvements AT claims to have made are real, that's just a nice bonus.
But yes, at $1700 list, there is no way i would purchase that over the 950.