I have done the section thing to sell someone on a full detail instead of just a one step
did one half panel with just 80 one time over, then the other half with 83, then 80....needless to say, this person was shocked in how much better the 83/80 combo worked....so I used IP and FPII on the whole car and she was saying things like "its a brand new car, you're going to be busy with more cars once I tell everyone, wow it looks really good, much better..etc" all throughout the detail.....all i could do was smile and appreciate her gratitude
the test shots work well....and like the other person said, it leaves them with no choice really, not that its a bad thing when it comes to the car...most people would spring for it once they see the results in person....its the uncertainty in some who dont want to spend the money to have the car two stepped because they dont know if its worth it or not....this shows them it is