Are 4 axle grooves better than 2 grooves?

No, our PRO axles are machined axles, precision designed by mechanical engineers. We cut grooves for a purpose. One groove under the axle head removes the corner, so the axle rides flush against the axles head, thereby reducing wobble. The other, wider groove, is strategically placed so it is always in the center of the wheel to reduce friction and so it does not catch the edge of the wheel. Four grooves are a gimmick. Consider this; if 4 grooves are good, why not 5, 6 or 10 tiny grooves!