Ok one of my concerns is in paragraph 6 above where I talk about the 3rd object. You say that “A brep face though, can be flipped to show a normal direction at odds with its underlying surface. The brep face normal does not affect the underlying surface.” When I use BrepFace.Reverse(0, True) the surface’s normal changes to the other side and then BrepFace.OrientationIsReversed gets changed to the opposite value. So it appears that BOTH the surface and brep face change when using that method. So it appears that there is an issue here.
On the second object (paragraph 5) I used Brep.Flip(). The surface normal did not change so it appears that this method would only affect all the brep faces. I inspected the brep face and turns out it not only changed the normal direction but it also changed the OrientationIsReversed value to its opposite. One or the other should have been performed on the brep face, but not both. So it appears there’s an issue here.
On the last object (paragraph 7) I used Surface.Reverse(0, True). The surface normal was affect while the brep face normal did not change. This aligns with what you stated.