There are LOTS of reasons for the bow to be out of tune, walk back and BH tuning assume the only thing out of whack is the center shot or nock point. If ANYTHING else is out of whack then it won't work so good, as you found!

Other things to check:
- tiller measurement
- cam timing (yes even on a single cam)
- cam lean
- arrows, are they tuned, bent, aligned

It's really a fun game, LOTS of variables.