A.J.
I stopped measuring once my kids were through with the bottle. And my kids all resisted milk and since I myself hate milk I didn't push it. What I did do was make sure they had some calcium rich foods at every meal.
So, try not to stress too much about it. Just make sure he gets a cup with each meal & snack and is gaining weight. Not only does he need that calcium but he needs the fat to help build his brain. Parmaesan cheese, cottage chese, yogurt are also really good sources too!
A.