I decided to give this a try, even though I'm pretty happy with AS exSEA.

I recently completed one r/t (outbound had an hour MX delay; inbound was empty and fine). I wrote today to DL CSR asking if there was also a number of legs one could accumulate to qualify for the promo since often I have 3-leg business trips. Seems like a long shot, but I guess that all depends on how much they want PacNW customers.