Seems fine as is. I mean maybe I don't understand the rating scale completly and I am no math guru, but only 1 macine in the top 10 (AC/DC) and 2 more in the 10-20 range (Tron pro and Tron LE) have less than 600 ratings. One or two Extra high or extra low ratings is not going to sway anything very far from where it is at.
Plus if you look at Tron, the 2 machines are pretty much in the same spot which again in my opion seems like the ratings are doing what they are supposed to.