So that is a complete no...why not just say you don't.
Sunlight is not an example of 400umols uniform dude. Try 1700-2000 of uniformity. The sun is up to over 1500umols by 9am and stays that way until damn near sunset(past 6pm) . 9 hours of intense light for a DLI over 40mols...closer to 50mols.
So again...do you have any examples of the strategy(400umols) you are pushing? Ideally from your own work too and with cannabis. But will take anything to start.
Well there is documented research regarding light absorption for photosynthesis. The text I am most familiar with is 'Photosynthesis' by Hal, Rao published by Cambridge University Press.
Some people are looking for ideas to improve, some aren't as they are completely happy with their current system. I am only referencing publicly available research for ideas that are relevant to the discussion and stimulate some thinking. Useful information comes from many sources. For example, this is a great reference paper for the leaf temperature discussion and even mentions photosynthetic capacity:
http://publish.uwo.ca/~dway4/files/Way and Yamori 2013.pdf
Sunlight is capable of well over 2000 umoles of radiant power. Of that, roughly 1/5 (~400 umoles) of that is usable PAR spectrum absorbed by plants. That is what a number of plant specialists (eg. various biologists, botanists, etc) have come to generally accept, as for example, in the aforementioned university text. The plant can handle more light up to a point where the plant's thermal management fails and damage occurs, however it just won't increase photosynthetic rate.
I used sunlight as an example for the principle benefit of uniformity. At the earth's surface sunlight is uniform to exposed leaves throughout the plant. Radiant power from artificial light drops significantly over distance and benefits from uniformity by help putting light where it can best be used by the plant thus improving efficiency.
My point is that uniformity is important, probably more important than people are investing in.
Also, the optimal radiant power might not be 400 umoles, it could be 600, or even 350 but it is some number and once it is figured out that should be the target for all exposed leaf area.
(edit) yield/area is what you should be looking at, at least that is what traditional agriculture is concerned with.