I think the OP is asking a specific question and we are giving him a general answer. On certain short flights, LAX-SFO for example, the FAs will announce that there is a limited beverage service in Y and the choices are A, B, C or D. The choices are pre-poured on the cart and dispensed to the passengers in the foam cups. This allows the FAs to serve the entire Y cabin in a limited amount of time.

I believe this is what the OP may be alluding to since I certainly have not heard of AA being particularly stingy with their soda cans.