Ha, I just put two in an AD F-16 too! If they were purchased in a time-frame such that they might be from the bad batch, I'd just send them back. I was worried about the two in the plane I built as well for the same reason - they move a large surface and there is no redundency. In my case, I took two from another plane that were purchased awhile ago and that have a few hours of operation on them and put them into the F-16. Then I sent all my "suspect" new 8611a's back and they replaced them all.

In my experience if you send them priority mail, you'll have the new ones in about a week. Not much time penalty to get piece of mind...

Bob