Generally that's what I use, however sometimes the selection is at an angle, likewise the scale tool is also at an angle. The results are produced from that odd angle. What I have to do from this point is take the rotate tool and rotate to either the x or y plane.
I hate to use Adobe Illustrator as an example since it is 2D, but it too has x & y coordinates. In Illustrator, I can select any number of points and average them all to either the x or y plane. It's perfectly straight.
It seems with the scale tool, I have a few steps and I'm guessing whether the selected vertices are perfectly straight or not.
The scale tool is fine, but I was wondering if there was another method.
Thanks for your expertise,