This option is a peculiarity of the previous command. In this case, it will initially ask us for the elevation increase and then the tracker.
In this way, the end closest to the selected tracker will be increased with this elevation, maintaining the proportionality in the increase of the rest of the poles.
In turn, it will look for the tracker to the north or south closest to the selected vertex, so that this tracker to the north or south will be incremented in the same way. The ultimate goal is for the elevation difference between the trackers to remain the same, but applying the elevation to the trackers as described.
Below you can see a status before and after applying this option on the trackers highlighted in red.
From the previous image to the following one we have decreased the extremes of the tracker by 0.2, we observe how the elevation of the supports decreases proportionally, maintaining the difference in elevation between both trackers.
