Chris,
Marv Klotz is well known to a lot of us, and produces some very workable programs, but only if you understand machining and mathematics. He is a brilliant physicist who doesn't suffer fools gladly. Most of his progs are mathematically based, and if you don't understand it, you will get no leeway if you ask the wrong question.
His ball turning prog does work, and the tool he is on about is like a parting off (a plunge grooving) tool which has a square end to it.
That particular program gives you a stepped ball, and is dressed back with files to produce the finished article, just like Ralph said. I do the same sort of thing, but freehand by eyeball, and have had some acceptable results, without all the hassle of co-ordinated turning. It is all down to experience and trial and error.
Bogs