Are the 5 steps of natural planning, that David writes about in chapter 3 of Getting things Done (getting projects creatively underway) to be implemented or worked through each time I have a commitment to accomplish that is 2 or more actions to complete?

While I haven't understood the natural planning model as well as I'd like to, my observation is that it is comprised of 2 vertical focus steps and 2 horizontal steps accompanied by a brainstorming step sandwiched in the middle. Is this correct?