how do bartenders/servers handle "tabbing you out", when there's a shift-change?

My stepson works as a captain in an upscale restaurant. He gets the entire tip, then splits out to his team. He’s got a front waiter, a back waiter and a busser to take care of. IIRC, he gets 40%, the front waiter gets 30%, the back waiter gets 20% and the busser gets 10%. However, if his team does an outstanding job and they get a big tip, he’ll drop his cut to 30% and spread the extra out to his team. People clamor to work with him because they make money with him as opposed to the other captains, and the restaurant management has noticed this. He’s got a good future with them.