I hope I didn't sound like I was talking down to you Josh. I know you already have basic knowledge. There are many people who read these posts and take info away other than those of us who do the posting.
That said, If a tech takes a good smooth yardstick and rocks it back and forth it will rock smoothly. If there is a flat spot it will bottom out on it. Much like rocking chair does if the rocker has a flat spot. This works best on low crown panels that are difficult to "feel" with your hand.
Keep us posted on your progress.