All the new D28s I have seen require setting up, before they can be played. Odd when you think of the price the charge. I bought a Tanglewood 12 string for about £400 new, and it was set up perfectly. Just shows, that you don't always get what you pay for. My present 12 has a very shallow neck, and I have had to build up the back pad on one of my capos to make it hold the strings down effectively. So it could just be that your Gibson has a lower profile/thinner neck, and this is what the difference is