First, what Transmitter are you using. The 9C has an issue when mixing elevtor halfs, one noticably lagging the other. If you are flying a 9C, that may be what you are seeing. There was a thread recently about it, and the solution is to use a match box of sorts and Y the elevators off one channel. The match box allows you to reverse one half and then tune the center point so both halfs are syncronized. I've got on plane with the two servo elevators on a 9C, and I havent noticed it. Of course, I not that good of a pilot that I would notcie something like that.

Don