I think the moral of the story is.....ride with a flatter foot, get the top part of your foot out of the wind, get a more aero cleat/peddles, and you save watts.
I makes sense that riding with a flat foot would be better, *and* that it doesn't take much downward foot tilt for the entire pedal to be drafting behind the shoe. In that case I can't imagine that the pedal would make much difference.
How many people ride with the foot so flat that the pedal is important?
In the article http://www.ero-sports.com/...lay-zero-aero-pedals
it it suggested that the difference in drag between the two riders could be influenced by the difference in angular position of their feet. This is illustrated by two pictures with the pedal in the lower position.
However I think the foot position in the upper pedal position is much more relevant, since the relative speed of the foot in the upper position is about 10 km/h at a cadence of 90.
So in the upper position the foot has a velocity of 50 km/h instead of 30 in the lower position at a bike speed of 40.
Adding that drag increases square in relation to the speed shows that the angular position in the upper position is a lot more relevant than that in the lower position.
With a head wind furthermore, the wind farther from the ground should be faster than near the ground.
And I would say, answering the question of ruff, that the angular posion of the foot in the upper position is generally flatter with most people than in the lower position