Everyone would agree that you need to add extra lbs to dry pin weight for more accuracy. I will say however, when we bought our '06 Cedar Creek Silverback 33 LBHTS, it's dry advertised pin was 1800 and dry weight was 10,800 with max GVW of 13,800. Fully loaded for a week for 5 people, 1 dog, pin was just over 1900 and 13,000. So IMO, weights may differ greatly amoung mfr's.
That being said, here is a good example. Our new coach's weights from Mfr say: dry pin 2,888, empty 13,420, CCC 2532, max GVW 16,000. After we picked it up, went right to a CAT scale which resulted in: pin 2860, empty 14,000 (which leads to a CCC of 2,000). Fully loaded for a week (3 people, 1 dog, 1 cat), pin 3800, trailer itself 15,980 (which means we had 1980 lbs of stuff in it). Ironically, that means we had about the same amount of weight of stuff w/ old CC as well, BUT GAINED 1,000 lbs on pin which I feel has a lot to do w/ design of coach.