Well, that's my point -- I supplement the hand wax each week with a coat of the spray, which lasts (I would hope) until the next Saturday. I've left out the soap step, except when I planned to hand wax, for quite a while on my cars, and they have all remained glossy and gleaming after I rinse-and-spray-wax. No black cars, though.
Don't misunderstand, Critic, I know you're expert on this stuff. But I don't have a way or place to hand wash my car with soap and water at home. With the car wash's soap, I drip the stuff from the foaming brush onto the surfaces without touching the brush to the paint, then wipe the soap around gently with a sheepskin mitt before rinsing. You're saying the soap would not take off the "core" wax, the hand wax? That the hand wax coat would not be any worse off than with simply rinsing, and that the soap would mainly remove last week's spray wax?