Well as far as model rocket flights go, it was an extremely marginal, hold-your-breath, crappy flight. I only did it because I am a steely-eyed competition flier who needed to get the job done (i.e. wanted to win the big prize at a spot landing contest). Based on 45 years of model rocketry experience, mission accomplished would only happen if I used a B6-2, which would deploy the parachute over the target at the last possible moment and still be called a safe flight. I wouldn't recommend the B6-2 for routine flying, and I am not at all surprised the Estes doesn't.
I think you're hung up on Estes' numbers too much. Their data isn't sacred rocketry dogma or something. Maybe it's wrong. You have many people here telling you that the C6-3 works. It worked for me. It certainly works better than a B6-2. And when I tried flying this rocket with a D10 it worked too well, and I almost lost the rocket. I'd prefer to fly it with a C6-3. Haven't tried the C12 yet.