Over and over. Each plant is different how they grow. The Meter Squared is a constant that can be compared from one to the next.

Those numbers are under perfect, I mean scientific-perfect growth. I have indicas, mixes, and sativas, and each produces about the same at the size I grow them. I will let an indica go longer in veg before flower as they don't have the growth spurt, which indoors can really cause some issues if you don't stay on top of things.

Not only that, 6 growers growing out from the same mother, will not have the same production volume over the same time period. Variances in potting soil, nutrients, water hardness and included chemicals...

IN summary,,,,,just a guideline.