Hi there, I was just at the paed and asked how much formula at 12 mths, the doc there told me that in reality he doesn't need formula or milk, but ~600 mls/20 oz of dairy. She said milk is actually filling so to try to give it in other sources like cheese, yogurt etc. And then a couple of cups of cow's milk would be enough.
Have you spoken to your doc? Have you tried chocolate milk for now? Our paed said they use that as a last ditch effort when LO won't take regular milk.