unfortunately, I am not allowed to sen images.
But to explain it simple:
If I set the Radius to 30, the handle of the points will be set to 17,
If I use "Optical Correction", the handle will be set to 19.
It would like to influence the length of the handle.
Example: If I set the Radius to 40 and the Handle length to 31, the roundness of the curve is like the first one, but the beginnings of the curve will be much smoother.