My 10 week old is a fairly good sleeper, well I think so! He has a bath at night then 5-6oz and is asleep by 8pm, he then wakes up at anytime between 1:30 & 3am where he has another 5-6oz. However when he next wakes at around 6am he will only drink around 2-3oz before he starts getting fussy and turning away from the bottle as if he's had enough. Then 2 hours later he's crying to be fed again when he will drink 5-6oz.
Could he just be thirsty first thing instead??
During the day he is going around 3.5-4 hours between feeds.