It depends on the casino. Some casinos divide by the pit, others by the shift, and still others in a 24 hour period. There's a few that divide on a seven day split. All of these divide only amongst the dealers, no bosses.

Those boxes can get pretty heavy, too. Especially if the dollar chips are tokens! Think about carrying 30 racks of tokens! That's only $100 for the day if there were thirty people dividing.

-Tyrus