Changes in feeding

My LO gets breast milk from a bottle (fortified with extra calories because he was premature). Eating has always been a struggle due to his prematurity. He is about 8 weeks old now and takes on average 3.5-4oz every 3 hours pretty much like clockwork - even through the night. The doctor didnt want him going longer than 4 hours without eating for at least the first 2 months.

Lately he’s been doing this thing where he takes his usual 4oz at his last “evening” feeding (around 8:00), then wakes up about an hour later and takes about another 2oz. He’ll sleep for 3.5-4 hours, then wake up but he’ll only take 2-3oz at that feeding and 3oz at the next one too.

I’m just wondering if this is normal? Is it maybe his way of starting to work toward sleeping longer at night by waking up to take the extra milk and then just kind of snacking the next two feedings? He is going slightly longer between his overnight feedings than he usually does. He has a regular follow up with the pediatrician this Thursday so I plan to talk to him about all of this, just looking for some insight in the meantime.