By any chance, have you noticed whether the oil holes in the rollers of your Iwis duplex are on the inside run, or the outside? Mine (the one that was worn out at 3000 miles) has the oil holes on the outside run.The pins on mine were badly worn - supposedly the strongest part of the chain's design. I called Jason at The Chain Man, and he immediately sent a replacement FOC, even though it was Andy who supplied the original. He sounded genuinely surprised at hearing of the rapid stretching - "first ever" were his words. The new replacement also had the oil holes on the outside run. I would have thought the oil holes would be better placed on the inside run of the chain, so oil wasn't flung out of the holes under centrifugal force as the chain rotates.