Yea I was wondering what his thought process was (and where did it come from) that this test disproved? Nothing here really shocked me either, making power anywhere is all about how much charge you can get into the cylinder.
But this is where this test might poke a holes in conventual wisdom that smaller always fills better at lower rpm. I think it's not that hard to fill at lower speeds so it probably somewhat hard to F up.
Plus you look when adding a basic mild cam headers and 4 bbl to a low performance 2bbl engine they generally gain even down low showing they can use more airflow even down low.