One strategy we always use when booking any award ticket with Delta is to book my award ticket separately and then make my wife's ticket immediately after. The reason: When you book both together not only will you not receive credit for mileage, which is standard, but the second ticket will not receive frequent flyer miles, as well. We just keep a second window open online and then book her ticket as soon as my reservation is complete. Following this strategy she will receive her ff credit because the ticket was purchased separately. A day or two later we call Delta and ask them to link our tickets together for the free baggage perk.