There are many different versions of the contracts as they were tweaked over the years. While many of their contracts resemble each other, they were changed in order or by what was covered. Don't assume your contract is the exact same as everyone else's or one persons' contract' section is included in your own.
There may be two types of author contracts that differ in the verbiage of what your payment covers.
- Contract fee's to cover publishing your book
- Contract fee's to cover the publicist (not publishing) of your book.
This may be important in a class action suit where (1) may sue for breach of contract while publishing and (2) may sue where their book never made it to marketing.