taking a proven port and moving it to the CNC
Exactly: if the model* from which the data points were taken is successful, and the tooling is properly programmed**, the CNC product will work well. If either of these is not adequate, it won't.

* most common error I've heard of:
Customer: "I have an iron BBM. What castings and chamber volume do you have programs for?"
Shop: "................... What?" He'll use the one he has, even if it's from a different but interchangeable casting (906 vs. 452 etc.)

** running the program from fewer angles or at higher speed gives coarse finish and less accuracy on internal surfaces