Screw Modifier: "Calculate Order" checkbox -- what does it do?

Here’s the entirety of the dox for “Calculate Order”, but, what exactly does it do, and why isn’t it just the default? (It defaults to OFF.)

Calculate Order

Order of edges is calculated to avoid problems with normals and shading. Only needed for meshes, not curves.

Properly because it takes time and if there are no problems and it would be the default everybody would cry why is it so slow. But you are on of those guys who read the manual and if you get into problems now you know there is something… :wink: others overread the simpelst things… (i think order to the camera so depth first)

OK. At the (basic) learning level it seems instantaneous, but maybe in complex scenes it adds a bunch of overhead.

The thing is, it easily addressed a problem in this tute ( youtube.com/watch?v=PAcTIQWmizo ), which I sincerely doubt I would have ever found on my own.

, but maybe in complex scenes it adds a bunch of overhead.

While adding one screw modifier you have problems or not… What overhead ??
And if it cost time while not needed …