I wouldn’t wake him up at night, because he needs to sleep, and it’s also a blessing to have him sleep for extended durations at night. I would offer feeds more frequently during the day, every 3 hours instead of 4, and offer 180ml each time, trying to encourage him to drink at least 160ml each time if possible, and even more before he sleeps at night. But he seems to be putting on weight well, so I wouldn’t be too worried at this point too:)
Hezel Tmr