after some hours of snapping test, I can´t find a way to align snap points nearby another point.
In lightwave, I can do that with align, and in this case align to last points z-axis, so the first image is the end result I want.
I can also use the axis transate tool in Lightwave and middle mouse click and move the mouse till I get dotted guideline when that is aligned with the point of target, then release the tool and the points will snap aligned as they should be.
Just need to find a good way to do that without working with a defined grid in blender.
Again…first image is what I want as result after moving two points down to have a straight section.