I know Util % isn't everything but maybe that could of done it?
Are you sure that's what caused it? I try to keep balances on a few cards regardless. I lent my father some money to pay most of his credit down and it went down a few points then back up. I don't know understand it. I think some lenders want to see some type of balance. Sorry 
@Anonymous wrote:
Paying down one of my credit cards brought my score down 9 points. Whyyyy?
All you need to do is scroll through the titles in this "Understanding FICO Scoring" forum to see numerous "My score dropped" threads. The common response is; it wasn't that trigger event, and you need to look deeper into your file and recent activity in the file to looko for other events and changes that may be the real reason.
Even with that, there's no absolute answer why, only general tendencies one can point to as likely causes.
