every vertices are handled similarly fine, no chunk border problems, it was bad only in A7 (but I had a workaround for it using d3dcomputenormals).

what you see rough is because of vertex distance i.e. terrain resolution. if it is set to denser you can get a much smoother terrain resulting in performance drop (I use 4 tiles as vertex distance i.e. 128 quants which is okay for me). and I used here high raise values to see changes clearly. moreover there is a smoothing option to post process your rough terrain by a few clicks to get something really natural.

Edit: also the selected brush, and the manipulated area size have effect on the final smoothess of distorsion.