At 100 skill in the appropriate armor and while using armor of 100 quality, the defensive bonuses provided by the armor are supposed to be doubled. Frankly I feel like the vast majority of royal armors look like utter crap to begin with, same with the heavy ones as well. The only exceptions being Full/Royal plate and Heay/Royal padded. But given the inherent nature of royal armors only being able to be worn by those with a high enough skill, perhaps it should look gaudy.