For the last several days, the unit has only been able to successfully calibrate when the head is placed under the camera. Moments ago, I ran two identically designed coasters at the same time and the differing results are shown below. They were positioned on the upper and middle right side on a left and bottom justified 12 x 20 Proofgrade maple plywood. I didn’t pay attention to be able to tell you which was uppermost.
The good one:
The bad one: