Phoenix86
Lifer
It was never decided. Serving size between products vary a shit ton.They were decided during a time before the average size of meals skyrocketed.
Personally I think serving size is based on content. They scale the serving size up or down to make the nutrition number come out "right". Then adjust the number of servings per container to match. Increase/decrease content slightly to make clean serving sizes. Voila, 2.5 servings per box.