That's how I would correct it, and .020 offset on the front, then .020 offset on the rear is .040 correction.
I'm not sure that would work. I got to thinking about this and if the scope is aligned .040" to the right and is centered and parallel to the bore, it should hit .040" to the right at 100 yards or 500 yards - makes sense to me at least.
I got to playing with it some more since I had to skew my Leupold Zero Point to the left side of the barrel. I played with the scope and when I turned the windage to the right, it tracked nicely along the little Leupold graph. But when I turned it to the left, it did not move the last 1 1/4 turns or about 75 clicks. I assume my scope is screwed up . . . ?