Oh, yes, absolutely! The account was only opened in June, and so was stinky new. Each time it went on, my score dropped, and each time it was removed, it rose again.
I had a score increase last October when I added on as AU on an 18-year-old account of my husband's. But at times, it has hurt my scores, as he seems to whip out the card three days before it reports balances to the CRA's, so that shows up on my reports as an additional account with a balance.
His scores (which are indecently high, up in the 800's) dropped when I added him on my Gold card, as it hurt him to have an account less than a year old. And now that I've dropped him and our younger daughter from the card, I suppose that if AmEx ever gets around to reporting this, his scores will rise again. And my daughter's will probably rise as well, because as a charge card, it doesn't help with util, and it's also a newish card.
AU accounts can definitely be mixed blessings! There needs to be a lot of forethought when deciding whether to do this.
* 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