Sometimes the adjustment can be very sensitive. Try bracketing. In other words, set the parallax where you think it should be, and check for movement of the crosshairs on the traget, and at things just ahead of and just behind the target. Choose which shows the least crosshair movement, and try checking it on something further in that direction (farther out, or closer) without changing the parallax setting. You should be able to find a point where parallax is eliminated. Once known, you will know which way to turn the knob to get you closer to your target's range. You can't always trust the markings on the turret.
Edit: Oops, now I see that all is O.K. Good on 'ya. I'll leave the post for reference though.