Hi, springcharm, welcome to the forums!
The score that you get from WaMu is what we call a PFICO, the "P" probably standing for Providian, which WaMu bought out several years ago.
A PFICO is what is known as a bank-card-enhanced score. In other words, it comes from a slightly different formula than that of your so-called "classic" FICO score that you get here. It weighs factors that are believed to predict CC behavior more heavily, and gives less weight to other factors. In addition, the score that you get toward the end of one month is actually the previous month's score. So your most recent score is actually from March. And finally, it is on a different score range, from 250 - 900.
So while it is not a FAKO, it is also not the same thing as the TU FICO that you get here. From message #2, it looks like maybe your util (utilization) last month went over a certain percentage point. It's not the total dollar amount owed on your credit cards (although actually, $10K is quite a lot!) It's the percentage of credit used out of your total credit limits.
Calculate your total util by adding up all the balances that report on your statements, adding up all your credit limits, and dividing the total balances due by your total credit lines. The best util is under 10%.
There are certain points in your util at which your score will either increase or drop; for instance, 10%, 30% and 50%. (There are others, but these are "for instance" change points.) If your util just went from 29% to 31%, your score would have dropped.
And it's the amount that reports on your statements, not the amount left after you make your payment.
Paying the car loan might have contributed as well, as scores are helped by having an open installment account. I'm just going with the messages that you got on the e-mail alert.
* 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