@peachfuzz and @bob31 coming through with better explanations of this than I’ve seen in a while.
The breeders know there are too many variables to give a yield per plant. So they give it in area, and within reason it doesn’t usually matter how you get to that square meter of plants. 1 plant, 2 plants, or 9 plants. Less plants means longer veg time and more yield per plant. More plants mean shorter veg time and lower yield per plant. But either way should have potential to produce roughly the same amount.
That being said, breeders estimates can be a little difficult to reach for new to average growers. I don’t want to say they lie, but you would probably have to have your $hit together to attain high end estimate. In your case, with a high yielding strain, you should be looking to be in the neighborhood of between 500-1000 grams for a full 4x4. Not the a gram per watt is the norm, but is attainable with a solid grow and the right strain.