I would REALLY check with your Pediatrician first... being he was premature, and per the specific instructions you received about the frequency & amounts of feedings he must have.
Premature babies have specific needs versus a full term baby. It cannot be compared.
Here is a link on premature babies:
Your son is now 11 weeks old....typically, at 3 months of age, this is a growth spurt time, and they typically feed more and more frequently at this phase. But again, he was premature, so I'm not sure how this time-line would apply to your baby.
His intake is... 3 oz. or less per feeding. How often to do feed him... about every 3 hours?
I'm thinking, since he had "weak jaws" when he was born...and had to be fed through a tube... I would REALLY check on this again and follow up on it. Weak jaws doesn't just go away when you bring him home. See a Lactation Consultant... and check with your Pediatrician as well... you want to make sure that (1) he is nursing/suckling properly....as this impacts their "ability" to feed. (2) make sure he is intaking enough....as this directly impacts their growth and weight gain (3) is he having enough wet and poopy diapers? (4) is he gaining weight and growing appropriately?
Sure, it's generally great that babies sleep well at night. But since your baby was premature and had issues with his feeding & jaws...I would really consult your Pediatrician. It's curious that he is not interested in feeding. SOMETIMES, this can mean that he is having a hard time suckling...I have 2 friends whose babies had this problem... and their babies were not feeding well nor gaining appropriate weight etc. I would really check on this. Sometimes, lack of intake, can make them lethargic...or dehydrated. Best to make EXTRA sure.
I would be doing the same as you, logging everything, if that were my baby. Your'e doing a great job of monitoring him... I would be the same way.
Take him to the doctor and check, also see a Lactation Specialist. It could just be that your baby is a good night time sleeper....but just double check with the doctor, since he also seems uninterested in feeding.
Take care and all the best,