I think you are being a little unfair.
The usable area was originally designed to be 12x20 inches. During development of the project it was found that the deceleration of the laser head required some of that space, so the usable area was updated. Keep in mind that this change was made before the product was released, and the usable area dimensions change has been known for at least two years, and the changes were documented to the users.
The maximum usable area to my knowledge is still approximately 11 inches by 19 inches. The actual usable area will vary depending on the project settings. Projects requiring higher speeds of the laser head will have reduced available areas to allow the laser head to slow. Projects with slow speeds will use the entire available area.
This is fully and completely documented on this forum at the very least: Specs update