I went back and watched the ATK episode (S14 E3 currently available on Netflix) to see exactly what they said. They agree with pbear that the temperature of steam remains 212. However, the steam has 5 times the energy (owing to water being 'sticky' because of hydrogen bonds and, um, yada,yada...).
What this means is that steam can cook more eggs in the same amount of time. That explains my inconclusive results using one egg in each pot. Had I used 4 eggs in each pot, I probably would have seen the results I expected. More eggs would've caused a temperature drop in the water, requiring energy to be devoted to the getting the water back to boiling rather than being available for the eggs.
