Spot Slope Markers

This is an odd occurrence that we encountered today. When adding slope marker annotations in elevation views, we've noticed that it will pick up the slopes of not only the roof surfaces, but also the adjoining hips and valleys.

Is there any way to make them only pick up the surfaces? Otherwise, it takes a few clicks of the TAB button to find the right one. Not that it's a big deal, but it makes the user double-think the annotation which should be automatic.