I've gone from a $2K balance on a $50K available up to a $13K balance with no change in scores.
The person with the 800+ score probably saw a drop because scores are incredibly twitchy (reactive) up at this level. That was probably the only thing that had changed on his reports in a long time, so even a change in HELOC util affected him. It's not very common though (I suppose because 800+ scores aren't that common!)
* Credit is a wonderful servant, but a terrible master. * Who's the boss --you or your credit?
FICO's: EQ 781 - TU 793 - EX 779 (from PSECU) - Done credit hunting; having fun with credit gardening. - EQ 590 on 5/14/2007