hmm ok I see what your saying, and agree 10w wouldn't have yielded 6 oz. But to go the other way , I don't think if I doubled my autocob light to 120watts I would have yielded any better. I have to back off the light quite a bit even at 56 watts. I guess the point I'm trying to make is that wattage isn't a very good way to gauge anymore the potential yield. For example my Spider Farmer 1000 drawing 100ish watts consistently produces less Grams per Watt than my Autocobs @56 watts. To take it a step further my old viperspectra 900 drawing 400ish watts produced the least GPW of all my lights. When I grew in the 90's it was always around 1 to 1.5 lbs per 1000watts. Efficiency always changing.
I'm sure you may have stumbled upon "the grow boss" vids on youtube a time or 2. He's an old school guy and always ranting on that you need X amount to light/watts to produce X amount of bud or GPW. It's just not really true anymore. X amount of wattage does not equal X amount of bud. Don't get sucked into that old school way of thinking.