first of all you don't knao what PR is average, i don't know if you overpay your staff or maybe if you are the team with the best training and doctor enviroment ;)
But the main think is, that i expect the PR working must on visitors, the difference in advertise is low but is it very hard to compare the amount of visitor with the same succes - so it is hard to tell if a high level PR is a waste of money or not for me.