Gerald,
I took a look the Matrix and I see what you are saying. I did not look at all of the Level I National Standard vids. Here is what I think. When you pull up a particular detail and click on the Drills tab, you will see a column on the left of the video box that will have a list of one or two or three drills. When that is box to the left of the vid is empty there is not a drill video for it. Not sure why.
Take a look at the Skills Concept videos and you will find more drill videos.
Are you training for level I? If so when is it and where?
Greg Luce