More time less light

Have anyone ever done a wattage/intensity check with autos to find a sweet spot for wattage. In my mind I feel that because autos get atleast 6-12 more light then a photo plant they could yield better with less intense light. In theory an area I would use a 600watt light I would use a 400?

I'm not sure that it really would be possible for an auto to yield more with less light, but I do know what you mean in that they could yield roughly the same with perhaps slightly less intense lighting because of the prolonged daytime hours they recieve in the bloom phase compared to photoperiod strains. But assuming that it's not so much light that it's light burning them, I don't see any situation where less light would increase your auto yields.

how would you even know if you got any more , or less ? when you have no reference.

I didn't think you needed a reference to know that, generally, less light equals less of a yield? I do know that I (on average) yield equally or slightly more off of autos under a 1000w and 1 or 2 315w cmh's in a 6.5x6.5FT tent (depending on temps) as photo's I grew under a 600w in a 3x3FT tent, I assumed that experience would count as a reference for my own opinion? In any event, how do you know I have no reference?

I've never really followed that "watts per sq ft." stuff - I know some people are fanatical about basing their grows on that stuff, but I've always focused on the power of the light I put directly over each plant. And I've settled on putting 400 watts over every plant on a 24/0 schedule. I've tried as low as 100 watts and as high as 1000 watts...on dozens of strains over the years and I found that 400 watts had a significant enough increase in yield over 100/200/300 watts ... but found that there was a significant decrease in the increase of yields after 400 watts - so much that I don't think the extra power burn is worth it.

I guess if you wanted to break down my watts to sq. feet...I generally give my plants 2 - 2.5 x 2 - 2.5 feet of room.

And I'm with Logan on thinking that getting a higher yield with less light is not a likely outcome.

logan every seed gives different amount of energy in my opinion, go ahead, try it then, and put your mind at ease ?

Not sure what that post means, iNFID3L, as in every strain producing different results, or every seed being a different pheno producing different results? Either way, my mind is at ease, no worries.
Anywho,as for your post RStone, did you find there to be a 'sweet spot' between the low and the high end of light output? I've always felt that the primary constraining factor about high light output to be, unfortunetly, heat. But I know what you mean, in that, you may see a double of your yield when switching from a 200w HPS to a 400w HPS, but not see a double or more in yield when switching from say a 400w to a 1000w. Unless you supplement with co2, maybe, but I'm not 100% sure if extra co2 allows the absoption of more light or not.