I have noticed that when this issue comes up, people will argue both sides. Someone has to be right but I have never decided who it is. I think it doesn't matter, for these reasons:
How accurately can you estimate distances? This is the key to the whole system. If you are terrible at distance estimation, forget using the scales.
OK, you are great at it. Now pick up any lens with a depth of field scale. I have an example here, M50/1.7:
The scales that you'll apply your distance estimate to aren't very detailed, and this scale is actually usable.
Some lenses are just not going to have usable scales. Set my K300/4 at 35 feet. Even at f32, the scale says my DOF is from about 32 to 40 feet. I'm not going to use f32, and I can't estimate distances well enough to use any wider aperture.
IMO the technique is an approximation, and you will never find a situation where the format used makes enough of a difference in that guess.