I think they call that in Hurco terms an O-ring vent! Unless they have changed the programming since I was there, that is a vertical O-ring vent for sure. The software as far as I know can not step toward center for an I.D. O-ring or conversly step to the outside of and O.D. O-ring. (E,I,E,I, O-ring). Kind of like a horny Rotweiler humping on your leg. Safest thing to do is just let him finish. You may call Hurco U.S. and ask for Gerry Traicoff. He would know for sure either way. But as far as I know....Vertical Venting. Keep on Grooving Man. Sorry I could not help more.