RageKills

I play this game every day until at or above 70, but the scoring is not by percent. It is an arbitrary number based on difficulty with the easy words getting more points than the harder words. Ex. I was at 65% got three of the more difficult words as shown by their placement in the bottom of the list and have a new score of 68%. 3/35 total words should have added 8.5% to the score. Why not just assign each word 2.9%?