Agreed Ivietri. Not sure WGT has ever divulged their algorithm, but I've seen one that is close. Its how the weighted part works that can throw it off from a straight average near as I can tell.
Joey
Here is a thread where this has been discussed before. It contains a calculation that gets you pretty close to your WGT average, have a peek.
Thanks much A-Lee,
Will look into it a bit more, but I think I'm ok with it now. Sorry for the delay getting back to you, I was hugging my kids, lol.....