You have to be careful about scallop routines. Without the complex arc segmenting, the finish is less than desirable since the G-Code will revert back to line segments.
Not all controllers can handle arcs not parallel to the xy, xz, and yz planes. That is, they can't handle G68 commands in such a way to rotate the other circular planes.
Even fewer CAM systems can output the proper code.
Try this:
Rotate your construction coordinate system for the side view 45 degrees along the Z axis. Using this rotated coord, draw an arc.
Switching back to the top Cview, the line should look like a simple 45* line, from the side, an ellipse.
Now try to use that as a path for the cutter. Did the CAM convert it to a bunch of line segments?
In Surfcam, and others, there is usually a checkbox for arc segment output. This will greatly reduce the code size while providing a much better path based on arc when possible.