Terraform and level land in a rectangle shape (by holding Alt). Once done, extend the terraformed land up or down (ie vertically). Place your mouse at the left most spot overtop of existing terraformed land (Ie. I want to make the land the same height and width but going down farther then the original terraform). As such I place my mouse on the previous terraformed land and hold down alt and drag to the right and down until the width of the green box is the same as the width of the previous terraform. The green box looks like it's the exact width of the previous terraform but when I go to do the terraform, I get one extra column of boxes to the right (even in preview after the selection phase).
Ie. the green box preview does not match the next step preview where you are able to set the height of the terraform, and the end result is also one column of grid cells bigger.
