Well, you know that negative control points work in conjunction with positive ones to ‘restrict’ them – they don’t work ‘on there own’ and as such cannot revert global adjustments just by adding a ‘neutral’ one, also not in Viveza 2.
But what I realized some time ago, when you have been working on a pic, have used local adjustments etc and then decide to use another preset, it deletes your control points and all your work is vanished.
→ SilverEfex Control Points - Automatically being deleted - #5 by Wolfgang
While for now this is no real problem in Viveza 3 (there are no global recipies you want to try then), this is a major setback in SilverEfexPro 3.