I had my dad order an iPhone 5 for myself on Sept. 22nd. We don't live in the same house, so yesterday he called Customer Support to see where he phone would be shipped, but he had to correct them so it would be shipped to my house. Now the ship date has been switched from 10/16 to 10/22, while other people who ordered their iPhone 5s the same day or a few days later are now getting theirs shipped this week. Whats up with that?
Perhaps the fact that the address change was done late (rather than having it done immediately after the order was placed) could have something to do with it. You (or your father) can contact them to ask why this is. It definitely could have been worse. They could have stated the change couldn't be made OR they could have canceled the original order all together and re-ordered with the correct address...which would have pushed your delivery date further back than just 6 days.