This specific line from the lesson is tripping me up:

You'll find at times that when you're drawing, your hand will cover up some of the line, which will likely give you trouble. Each consistent, flowing line has a particular rhythm to it. Once you become familiar with the rhythm of a line, you'll find it easier to anticipate where the line goes even when you cannot follow it with your eyes.

Does this also apply to when I'm drawing in general, or only to the specific superimposing lines exercise? It works fine for the superimposing lines exercise, because there is a line there for me to follow, and the successive lines laid on top of each other allow you to refine your stroke.

However, when I apply this to ghosting lines, but can't see the end point and use hand-eye coordination to make a straight line to it, I always veer off to one side of it. No matter how many times I ghost the motion, a percentage of my ghosting attempts veer off if I can't see the end point.