Wow! 15% is the highest I've heard, too. You can still add your own flavorings to it, though. Run your fingers between the skin and meat and sprinkle some of your rub in there. Or try some aromatics-- quartering a small onion, and likewise an apple, along with some sprigs of fresh rosemary and a cinnamon stick, and placing them loosely in the cavity during the cook will add some nice flavors.