Is your geometry good? By that I mean are all the fillets tangent, face normals the right direction, any undercuts that shouldn't be there. Did you try doing an optimize face to clean up the model?
Sorry, I still don't know what you are trying to cut.
If you post a picture, display the part geometry and cut area.
Zlevel_corner is for rest milling material left behind by a larger tool.
If you are trying to machine the blend, I would use streamline. If you really want planar cuts, use zlevel and optimize the cut levels so they don't spread out as the part slope gets flatter.