I'm not Midnight, I'm barely early evening, but installment loans only help mix while they're open.
That's why we sometimes have angry members post that they paid off their last loan (car loan, student loan, whatever) and lost XX number of points.
Mix looks at your open accounts.
I don't think it's a huge issue if you have a really long credit history, though. Even the FICO wonks don't expect 70-year-olds to have mortgages and car loans, although one day they might still have student loans, the way those are going. At any rate, there are plenty of people with 20+ year histories and their only open accounts are revolving, and their scores are doing just fine.
And OP, yes, it's absurd, but the very presence of CFL's, open or closed, is a ding on your scores. But it's a small ding. And if carping about 5% util and closed CFL's is the best that your reports can come up with, I'm thinking that you're doing very well.
* 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