Got my set on my flight to the London FT Do and kept them for future flights until I find another two-pronged adaptor for my NC20s. SONY has been most unresponsive to my emails requesting a replacement. A few summers ago, AC was selling the old style headsets in Y for about a month, for $2 and you kept them. This didn't last long, and they reverted back to the freebies.
Would you not just get a mon signal in one ear by breaking off one of the prongs, given the way they'd be wired?