Hi! Fancy seeing you here ;\)
Freddie has nowhere near 20 oz - well I dont think he does - we're mix feeding so hard to tell!
On his 3 nursery days I send him with 2 6 oz bottles ... I generally get one back with 2 oz in it and one with 4oz in it. He drinks about 4- 5 oz when he gets in then has bf before bed and 1 maybe 2 bfs through the night. Depending on how much he's taken in the night depends on whether he wants a bf for breakfast or not
Try to make sure he has lots of yogurt, cheese, fromage frais etc etc to make up for the milk he doesn't take.
He'll drink out of a beaker for his daddy - not for me. Mind you he'll eat off a spoon for nursery - not for me.
He's headstrong and awkward I can't think where he gets it from