The old school way works. The difference is too great to ignore and the tech should have aligned it better than that. One thing to check before using the adjusting bolt extension as a guide is to make sure that the cast end caps are properly seated. I have had bikes in my shop where the cap was not properly seated on the end of the rectangular swingarm and this would relate to a difference in the amount of projection. Rather than using bolt extension, I would rather measure from the back end of the flat metal bracket that moves with the axle when you adjust the chain. As long as you are at it, make sure they have the slack right as well.