@daedalean --
That's cute... You think there is a "standard" contract.
There are entire structures and teams from the artist, through their representation team, to entire structures and teams on the Apple iTunes side that all work together to ensure weekly and monthly royalty checks are properly paid out.
It may even be so routine that even Spotify, Pandora, and other companies have found similar solutions and processes that have similar (if not identical) outcomes.