First check that all your ops have Motion Output under Machine Control set to Circular-Perp to TA. Usually are by default.
Next, on Cavity or Planer Milling try selecting Boundary Approximation under the More tab. Sometimes it can really shorten a path though at the expense of precise stepovers. Works best when the processor finds spline boundaries to trace. Check the Help on this.
Another thing is if you set tolerances way tight, it sometimes goes to all linear to better match a contour.
