Can't wait to see how your tool measures up against the Leaderboards that were first in testing in S2 and have been refined by Mr. Tod since Season 6. I mean 2013 isn't over yet, so who knows maybe S9 and 2013 will come sooooooo soooooooooon(tm).
Theoretically, you could get as high as you want if you have access to unlimited DPS/HPS.
A back-of-the-enevelope calculation shows that if you have a perfect match, i.e. you do 100% of the damage in the entire match (not just your own team), perform all 15 kills yourself, do 100% of the healing, get perfect style and utility ratings and do 4.5k dps and 3k hps, then you will get 12 points for the match.
I'm currently in the process of reworking the utility and style ratings. Once that is done, maybe the formula will be sufficiently stable to give some more detailed explanations.
A big future project that I have not yet undertaken is the implementation of team-detection, so that I can better tell whether one was fighting against superior forces or merely shooting fish in a barrel and then use this to better rate a player's performance.