My hubby had a grueling business trip on NW two weeks ago, had to go to DCA, drop off documents, on to Seattle the same day, drop off documents and four hours later back to DCA with the signed docs and then on to other places. NW has credited all miles except the flight from SEA to DCA. On his account it says "duplicate destination". Doesn't he get the miles for this?? If not, why not? It was part of his ticket, obviously paid for. With miles doubling this is a big chunk missing.