Feeding

My baby is 11 weeks old and I was wondering how long between feeds should he be going; he's formula fed; it's just that before he was going 3hrs between feeds and at night he would go 4-5hrs between feeds then 3-4 then again every 3; today I've noticed he's going longer or for instance ate at 5:00 had some awake time and because we ran some errands didn't go to sleep so then ate again around 8:00; came home at 9:00 then started to get him settled for his nightly routine bath at 9:30 then to eat again but he refused and just wanted to sleep; he did this earlier too is it ok for him to do this