How many axis 3, or more
Do you plan to use a tool with a matching angle? Planar Mill
Or use a ball end mill to make multiple passes? - Fixed Contour
Or tilt the tool axis and cut with the side of the tool ? Variable contour
The tool you have is a Ball Mill - you can't cut a non-planar surface with a Planan mill operation
That is correct
If you want to use Planar Mill, you have to be creative with setting your parameters.
Otherwise, another operation might be more suitable for this feature.
I apoligize, I should have tried this first
Here is a tool path using Planar mill on an inclined face. This can be done in Planar mill, see attached file with NX11 .prt