Orthogonalization introduces error and our robust solver can work well on steep inclinations.
Q: It has been removed in WS12 the orthogonalization option of the grid, previously recommended in case of high inclination values. Why?
A: The core routine that performs interpolation to constant height always assumed the grid columns are vertical (thus, in general, non-orthogonal), and the orthogonalization led to the interpolation being quite wrong near the ridges. The GCV works well with steep inclines, so the orthogonalization is no longer necessary.