The three fitted parts show it pretty clearly.
The left example shows blue surfaces indicating a positive draft angle
The center is green indicating a zero angle or vertical relative to the CPlane.
The right example faces are showing red indicating a negative draft angle.
The controls let you set the angles where the colors change.
You need to set the color upper and lower angle limits. Angles above the upper limit are displayed as blue. Angles below the lower limit are displayed as red.
Thank you Wim! This is the clarifying info I didn’t know I needed to understand why it would work on some geometries and not others. Appreciate the reply!