When you have the detailed text output overlay active (long-press OK), and the display is halted (HALT shown), and THEN you change V/DIV, the Vmax etc., values are incorrect. In my opinion. The halted waveform displayed was measuring a particular instance in time - the Vmax for that time is constant. It is not dependent on a subsequent V/DIV setting. The Vmax should only be updated based on "live" readings, not the stored reading displayed during HALT. When HALT is not selected (i.e., it's running) then the Vmax is correct, within rounding errors.
To reproduce: Enable text overlay (long-press OK). Then HALT if not already halted (press OK).
Now change V/DIV. You will see Vmax go through huge changes in value - when in reality it hasn't changed at all.
This is a UI bug, in my view.