So, only if UseSmoothing is true, SetCriteriumWeight has effect.
Only if UseSmoothing is false, SetParType has effect.
I also think that the documentation should be improved here regarding the Smoothing.
In OCC 6.3.1 Release Notes I found the following:
Advanced approximation method (implemented in class AppDef_TheVariational) has been
included in algorithms for creation of curves and surfaces:
When I tried smoothing with more complex surfaces, I often got exceptions. Does anyone have experience with smoothing / using AppDef_TheVariational? What are the requirements in order to use it successfully?