My comment was directed to Theslightedge, who quoted a different price and explicitly said these are the newest version of the headphones.
Though not sure where you are quoting the second piece from - on Bose's website, when comparing the two, they say they're about the same just QC30 has newer features like wireless and ability to throttle the noise cancelling, etc. Also the numbering system... pretty indicative that they are meant as a newer model of the QC20.