Hi there! Firstly, can you post your routine so we can take a peak?
My thoughts are that maybe he's still tired at his 7am wakeup, have u tried getting him back to sleep at this time, he may need it.
many babies stay on 3hr routines altho the norm for this age is 4 hrs, I know my Lo was on 3hrs for a long time. If you do want to extend then u have to put up with a little bit of fussiness! I suggest increasing by 5 mins time between feeds for a week, then 10 mins and so on, r u BF or bottle ? Maybe u need to increase the amount taken at each feed to allow for longer stretches between feeds.
Dont think you mentioned how old your LO is , it may be a growth spurt which would explain the extra tired and extra hungry