Why does a Motor6D keep correcting itself when I set it's angle?

So I was working with Motor6Ds today, but whenever i tried setting the DesiredAngle first then the CurrentAngle, the Motor6D's angle never reached the Desired Angle. I was working on something along the lines of this:

Neck.MaxVelocity = 100
Neck.DesiredAngle = -- [insert number here]
Neck.CurrentAngle = Neck.DesiredAngle

It never worked no matter how much I tried. But why is that so? I tried overriding the correction of Motor6D angles, but this isn't working apparently. If you know what I mean, you should probably answer, since I am terrible at explaining questions like these. Thanks.