As you know 50% of the work is stitched from the back of your card and 50% is stitched from the front. The stitching diagram shows you the view of the front of the card. When you turn the card over to work from the back you get a reverse image of the pattern. If you are working on a circle or line it is easy to see which hole to use next. However, if you are working on an area with random dots it becomes more of a challenge.
You get a similar problem when there are a number of threads crossing the area on the back of the card and some of the holes have become obscured.
When this happens to me I find the next hole to use by looking at the front of the card. I then push the tip of my needle through the next hole to show where it is on the back.