When SketchUp makes an ellipse it takes a circle and scales it so it becomes an elliptical shape. This changes the length of the line segments that make up the ellipse. Is there any way to make an ellipse made of equally sized line segments?
There is a similar thread here: Elliptical array
Although the discussion is more about evenly spaced items along an ellipse, you can use the same approach to creating a group of edges.