Keeping in mind that HP equates to many factors such as will, morale, stamina, luck, divine favor, armor absorbing impact, skill, and so many more factors. So on a roll that misses that is described as not contacting the target as some of you are saying you see as a "miss" it can burn some of the above equating to a loss of HP. Eg on an attack that the defender avoids he had to work hard to avoid the attack (stamina burnt which can equal HP) or Luckily avoided the blow (Luck can = HP). A Miss can still be described to of caused HP damage for a lower amount than a "Hit" would of easily if you keep in mind that HP are a broard abstract concept.