Should I change baby’s bedtime ?

My 4 month old is drinking between 4-6 oz of formula every 3 hours (3 hours are per pediatricians instructions ) and sleeping through the night . His last bottle for the night is usually 9:30 pm and sometimes 10pm on weekends . I noticed that it’s getting harder to wake him up for his last feeding and it’s sometimes a struggle to get him to take even 3 oz. He’s usually passed out sleeping by 8:00 or 8:30. I’m thinking of making that his bedtime but since we don’t get up until 5:45am I’m wondering if that’s too long without a bottle and if that’ll give him enough oz for the day ?