I'm not sure what is going on with the percentages on your site. I am going to have to look at it further and figure out what to do. The code should work for bigger numbers the same as it does for smaller numbers.
You can go ahead and take out the code for percentages for now if you want until I can figure it out. It doesn't make sense why it isn't working, though. Apparently, the threads and posts being that big of a number must make the percentage code do something wierd.
I'll let you know when I have something for you to test (since my baord is so small).