I am having trouble with camera anchor points in Motion 4. My experience with anchor points with respect to layers is that you are able to reposition the anchor point so that you can set different rotation points and other things. When I am in "Perspective" view and am looking at my camera framing my scene, it does exactly this. That is, when I change the anchor point, the camera moves so that the anchor point is in a different position relative to the camera. However, when I select "Camera" view, the view is as though the camera has not moved; the graphic displaying the camera and where it should be framing is in a different position, but the view does not change.
Similarly, when I start in "Camera" view, and play with the anchor point settings, the view does not change. I am unable to achieve my desired rotation effect without knowing how (somewhat confusing) camera anchor points work.
You should not be adjusting the camera's anchor point as it will not help you with the animation. Depending on what animation you're attempting to achieve, you want to use the framing or viewpoint camera which alters the camera's anchor point to one of only 2 possible positions.
With a framing camera, the anchor point is in the center of the viewing frame. With a viewpoint camera, the anchor point is on the camera body.
If you can tell us what you're trying to do, we might be able to give you pointers on how to accomplish it.