A plunge point is one in which the tool makes a downward movement in Z. The user has control over these by using the "plunge point" attributes in his roughing and finishing passes. A common point of confusion is when the user tries to set a plunge point for his finish pass. If you look at the toolpaths carefully, you'll notice that in many cases no "plunge" occurs between the roughing and finishing passes -- the tool simply moves via a feed move from the roughing pass and into the finish pass. So the technicality comes into play, and the plunge point is not used. Unfortunately, we have no way to tell FeatureCAM where to start the finishing pass in this case. But you'll notice that if you turn off the roughing pass and the finish bottom, then the finish plunge point will be honored. So a workaround would be to break up your feature into to separate features: one for roughing and one for finishing.