I have the same type of thing happening here. one boy comes in at 7am. By the time he gets to my place he's at his second 8 onces bottle. Then his mom expect him to drink an other 2 bottles during the day...
of course he doesn't eat for me since his belly is full of milk.... so i started giving him one sippy at lunch and one at the pm snack. I just send him back with the rest of his milk... ( usually its his second bottle.)
His mom was wondering why her 20 months baby was chubby..... thats the reason!