Re: hi ho Silver, The Lone Ranger rides on....
The SAG/AFTRA contract (2011) is available on their website
This is what it has to say about theatrical billing:
Billing: (Television & Theatrical) The Producer is required to honor individually negotiated billing as described and agreed upon in the performer's individual contract.
In other words, this is negotiated by actors and their agents.
(Or, just what Dennis
Batman does not eat nachos.