So baby is 12 weeks. I EBF. When I have to leave him with Meme or Dad he gets a bottle of expressed milk. It isn't often that I go. I can pump 5oz with both breast and still not empty them. When he BF I get empty on one side and half way on the other. I know he's getting at least 4-5oz (did a weighted feed), but when he bottle feeds he will only take 3oz. Is this okay?? Normal?