Print out both EQ reports (high score and low score) and go through with a yellow highlighter. Something is either appearing and vanishing OR is changing status to cause this. Highlight every difference, no matter how trivial it seems.
Then call EQ PDQ. I have their Credit Watch Gold, which comes with a phone number to real, live human beings:
1-866-640-CARE (1-866-640-2273), 7 days a week between the hours of 8:00am - 3:00am Eastern Time Zone
I don't know if you can fast-talk your way past not being a customer, but at least it's a number.
As ByrdMan said, it sounds an awful lot like a split file, although it could very well be what llecs was describing as well. Do you already have a face-to-face relationship with whoever's doing your re-fi? If so, I would print out your scores and reports for both scores, and see if they're willing to go with the higher one. Lenders ought to be familiar with this increasingly common problem with EQ. (It happens from both thick files getting too big for their alloted size and from frequent score monitoring pulls.)
I hope you can find someone with common sense who can evaluate your situation and see what is happening, whatever that is.
* 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