I Disagree.
I suspect that a fixed panel has an optimum direction for collecting energy and a panel oriented any other way will collect less. If you accept this, you can see that mounting any panel in any other orientation will produce less power than one which is set to the optimum.
Having panels facing different directions will mean that they peak at different times and that will mean that you'll spend more of the day with a panel at (or close to) the optimum orientation *for that time of day* - this will make your power supply more even across the day (but not completely even, as you seem to claim), but the overall energy you collect will be less.
As you say, power = voltage * current; the kid's measurements were "open circuit" so current was almost zero and so the power he developed was also almost nothing.
As for the power "wasted" moving the rotating panels (or mirrors); I suspect that the companies involved have done their sums, so the energy taken to move the panels is significantly less than the extra energy collected.
