Hey Gregg,
Do you have the area in mind where the rounding hits the flat part, if so:
t is a battle of the Phong Tag, when to smooth parts and when not. The example scene had a problem in the edge (on the right), which might have influence in some cases even far away from that. I assume that was not part of the question.
The Extrude [Nurbs] builds five elements if set to fillet and caps on both ends. These five elements are not really connected, they have all the vertices/points at the same position. You can see how that changes when you use a Connect Object and experiment with the Phong settings there. (See image)
Sometimes a Subdivision Surface Object [HyperNURBS] helps, sometimes the Phong Tag and its settings with a Connection Tag.
If you have the option to make it editable, use the Optimize Function and check if there are edges selected for a “Phong Break”. A Phong Break is similar to two edge, at the same position, but not connected, so no smoothing.
With A or without B Connect Object
https://www.amazon.com/clouddrive/share?s=8DIyyJHbQaohnhwz6vWG08
Extrude A vs Polygon B and phong set to the parameters mentioned above
https://www.amazon.com/clouddrive/share?s=LaWiod-qRdYnc5TW_h7k0A
All the best
Sassi
P.S.: all images have a Sky object as reflective background with the noise set to scale 3% instead of 300%.