Maybe I somehow don't get this reverse auction.. but why does the seller need to transfer coins in order to sell his chips?
The coins are sent to John for escrow so as to make sure the seller can give our address to zefir for shipping, and our coins have been sent to John for escrow. After zefir ship the chips, the escrow coins and the coins for the chips will be released to the seller by John.
Thanks for your interest.