See, you guys are missing the point.

Seed companies base those numbers on per square meter, or some other plotted figure. Since all plants vary depending on size etc, they use a formula per square meter to get those numbers, so basically within a 3 foot by 3 foot section you can hit those yields fairly simple. Ask them, they will explain it to you.

I do completely understand what the main poster is saying though, it is a misconception that most people don't realize until they go to harvest and end up with a max of 6 ounces/per plant.

The yield is based on a particular area, squared. Hopefully that is about as honest as you can get. Obviously they wanna sell a product, so they aren't going to advertise 4 ounces per plant, when other companies advertise 400-600g.