I recreated my measurements, and Excel reexamination of the attached files confirms that there is no discrepancy. In my mistake I must have been measuring the bottom line of the squarewave (which I had set at the bottom of the screen using YA-GridPos). Apparently I overlooked the negative overshoot at that time.
The attached files support that there is no problem. The present work around is to rename that file using the measurement parameter name as the file name.
Edited to remove errors.
gndpos.zip (50.4 KB)