Conversations get postponed for a specific reason: you can picture the other person's first objection and you cannot picture your answer to it. So the preparation that helps is not a script — scripts collapse on contact, because the other person has not read theirs — but having already thought through the two or three places where you expect to get stuck.
The structure here does one unobvious thing. Section four asks what you should *not* say, drawing on what you wrote in the setup, and it is regularly uncomfortable, because the grievance you have been rehearsing for weeks is usually in there. Under pressure that grievance comes out, it shifts the conversation from a request to a complaint, and the request never gets answered. Seeing it named in advance is most of what stops it.
Section five matters nearly as much. Difficult conversations go badly less often from the wrong opening than from continuing past the point where anything more could be achieved.