BowTech you say? Check that puppy for cam lean... but you should still be able to find center shot. (Even if it is way off center) Hmmm... What rest are you using? I couldn't get my Old Glory to tune at all with a drop away served into the down cable. Got rid of the drop away attached to the down cable and BINGO! problem solved. I don't know what it is about the Binary Cam that is so sensitive to cable tension but it's not the first time I've heard of this.

Edit: I see now NAP 2000. My NAP 3000 had a mysterious nock right tear I couldn't get rid of on the BowTech (It works great on my Hoyt though...) I put on a Whisker Bisquit and all the tuning probelms went away.