Imo, he is an idiot. If no money comes on, there is no volume, and the cumulative total is unchanged even though price changed. Or really, the volume is so light that it barely moves. If the time increment is small enough, there is no way to hide the side which has the most pressure. That is why I favor 1min or 2min obv, not longer periods.
Take care
Stay on the right side of the cycle!