Thanks for the post that this is active again. I was looking for west coast flights for the autumn, and this is the best deal but I missed it the first time around.
I booked ARN - HEL - JFK - LAX - SFO - JFK - LHR - PRG in October for SEK 12,838 (about GBP 1175). Both transcon AA flights and AY outbound transatlantic. 680 TP on BAEC. You could get at least 40 more if you work it.