Hi Burr, sorry I'm not really understanding this. What type of analytic surface do you want to get after editing some sphere points?

When you edit the points of a sphere, the original exact sphere is actually replaced by an approximation. That's because the actual exact sphere's control points are not good to squish around because an exact NURBS sphere has "fully multiple knots" (basically corner points) which will form a crease if you move them around individually.

- Michael