Garrett, I have no doubt in my mind that a forefoot strike is the best way to run. I simply wonder what the reasoning was behind defining "running economy" as oxygen consumption. I can see that burning more oxygen means you're burning more calories, but if you're also using more muscles, then that could help slow the occurrence of fatigue/cramps in specific muscle groups. That would permit you to run for a longer time, therefore making it more effective, at least in one sense, even if more calories are burned.
I wonder how much of the increased oxygen consumption came from the calves alone. In heel-toe, the calves don't play any substantial role, since the impact is all absorbed by the minimal elasticity of the cartilage in your joints (a bad idea, but that's what happens). With a forefoot strike, all of that force absorption is immediately assumed by the calves. Muscles absorbing force takes energy (and therefore oxygen); joints absorbing force just causes pain. Is 0.25 L/min a huge difference? Just thinking.