Regualted to what Jeremy. I don't know if Duralite actually tells you what the Powerbox regulates them to. Remember I had a problem with my Kingcat with the Powerbox and 7.4 Lithium Ion Duralites off a fresh charge. I changed my servos in the flaps and rudders to 8411's from 2721's and didn't have any more troubles with bouncing control surfaces. I find it odd with 8611's you are having troubles. I do believe I have 8611A's in my elevators and haven't had any problems there.
Good luck with the new engines hope to see you at Princeton.

Alan