@Anonymous
Ok just re-read and see that Discover is an AU, I guess this confirms AUs can't be used as "except one".
Agreed. The OP will want to report a small balance on his Amex or NFCU cards.
OP, definitely get a swipe in every 4-6 months (at least) on the NFCU card to ensure that it doesn't get closed down.
As far as your score drop, any score change that happens as a result of a utilization change will be exactly reversed if the utilization change is exactly reversed.
Basically, if Card X has a balance change of +$1000 and it results in a score loss of Y, taking Card X -$1000 back to it's original point and having that report would result in a score gain of Y. Any variance in Y here simply means that another factor or factors outside of that $1000 balance were at play.
