@golbinau--
1. There is no "rule" relating to above the title. The only "rule" is the one on the ticket, which forms a part of the contract between buyer and seller, which states very explicitly that there are NO refunds or exchanges.
2. A producer, or even a box office, can and often does provide flexibility, either according to custom (e.g., above the title, snowstorm, etc etc) or because it does not matter. So if a box office is sitting on 500 tickets for every show next week, they will likely exchange tickets for just about any reason unless the person at the window gives them a reason not to. But when a show is essentially sold out for 6 months in advance, even if a box office feels bad for you, they know that there are no exchanges with which kvetchers are going to be happy.
3. You assume someone is above the title as a matter of marketing. That is not always the case. Frequently, it is contractual, and I have seen contracts in which the details of how and where an actor's name will appear on the credits page goes on for more than a page. Sometimes, it is for insurance purposes.
4. Had LMM wanted his name above the title, you can be damn sure it would be there. I feel pretty confident he did not, and would have resisted if the producers had wanted it there.