Hi forge, here are some screenshots to help explain it more clearly.

Say you draw the first 2 points (defining the helix axis) in the front view like this:




So now the next pick is going to be for the start point of the helix, which will be constrained to be on this plane perpendicular to the axis (here we're looking at it from an angle in the 3D view to see it more easily):



But if you stay in that same front view, that plane that you see above is not easy to pick on, because it is being viewed directly from its edge. So in the front view that same plane would look like this:




So you need to move to a view for that 3rd pick where your mouse can kind of intersect that plane better which does not work very well if you are looking straight at its edge.

Hope that helps explain it,

- Michael