How to change the calculation of the pictures medium quality votes?

[Mish-A-Man]

How to change the   calculation of the pictures' medium   quality votes?
Since the coopermine gallery system is that the one vote can change a lot, it can be useful to change the calculation of the pictures' medium quality votes, and
if  changing those votes can be possible i would like to know how to be able to change them.
Voting system in the gallery  has the ratio of 0-5 which is basically 6 grades so i came up with an idea that it is more interesting to  give 5 stars to the picture that has a fair grade 4,1 instead the 4,5 , and also to give 4 stars to  the picture that has a fair grade of 3,1 etc. However, if there are five people who vote with 5 and one votes with 0 there is going to be a drastic change and transformation  of the pictures quality( so basically the picture won't have as many stars as it deserves). I wasn't able to find any similar ideas but i would like to ask those who know how to fix this voting to  try and help me.