Mesh statistics in 3D Slicer

Hello 3D slicer users!
I have a question regarding mesh statistics in 3D Slicer. When we select the points that we want to find the difference between the two models (Pick and Paint) we have the ability to change the scale, the radius or both of the points. I see when I increase the radius I have almost the same numbers and the only significant difference is the standard deviation, which is increased. Is that a fair assumption or I miss something? Also is there any rule on how big should be either the scale or the radius of the points?