DrPhoton I'm not entirely sold on the science behind your position, though I do understand where you're coming from.
What I'm considering as a possible point of gain is the time it takes the plant to replace the raw materials necessary for the reactions that occur within the leaf itself. Granted, I'm no biologist and I'm fairly ignorant where the actual chemistry of photosynthesis is concerned, but consider the following:
The plant is using raw materials to create stores of energy, namely carbohydrates by combining the ATP and NADPH created via the chemistry within each chloroplast. There is then a secondary reaction(s) that results in the production of the carbohydrates themselves. Each of these processes uses a raw material: water, carbon dioxide, trace elements, etc. What I'm wondering is if the process is rate limited by the amount of light that the plant receives in total, or the rate at which it can replace the basic raw materials to utilize the amount of light being delivered. It may be possible that by 'blasting' each chloroplast with many more photons that you can exhaust the store of raw materials within the chloroplasts and 'load up' the Calvin cycle (which is light independent). Meanwhile, as the light moves on to blast the next series of leaves the first plant can then spend a minute or two 'restocking' the raw materials resident within the chloroplasts and the various organelles that power the Calvin cycle so that when the super-high-intensity light comes back it can produce another large burst of photosynthesis and restock the Calvin cycle.
In addition to that consideration, I've also observed that the light on a mover is exposing a much larger percentage of the leaf surface to light energy than the stationary light by virtue of the changing angle of penetration into the canopy as the light moves. There may be some additional gain here due to the fact that the top leaves in the canopy are always getting light but the lower leaves in the plant are exposed to a higher number of average photons.
In terms of the law of conservation of energy (which is where your original premise is rooted), consider that my light on a mover is wasting considerably fewer photons on the floor and walls of the grow space by virtue of it being much closer to the canopy. Thus, a larger portion of the light energy being produced by the fixture is landing on photoreactive surfaces as opposed to non-photoreactive surfaces.
Again, this is all conjecture on my part and I'm no biologist. The experiment I'm running is certainly not what I would call an accurate application of the scientific method, but it should at least give me some anecdotal evidence as to whether a controlled experiment may be likely to yield significant data.