The purpose of the automatic gratuity was to include some of the employees that provide services, but don't normally come in contact with the passengers. I doubt if there is any way to find out exactly how the pot is divided. Even if you tip directly and follow the guidelines ($3.75 for cabin steward, $3.75 for dining room waiter, $2.50 for assistant waiter, etc.) the money still goes into a pot and is divided according to the protocol of that ship or line.
The gratuity has always been considered part of the pay; the hourly rate did not go down when the tips became automatic. It is generally believed that the automatic tipping was initiated because so many passengers do not tip.
To me the automatic tip is a convenience and also a minimum ammount. I expect a certain level of service; if the service exceeds my expectations, I tip extra accordingly.