When my daughter was born, I had been told by the younger doctors that she should go no more than 3-4 hours without eating. But she was so sleepy, it was almost impossible to do. Then an older doctor said to me that she could sleep as many hours as she is in pounds (she was 7lbs, so theoretically I could let her sleep for 7 hours without worrying). That advice was a godsend. She only went 7 hours once or twice right at the beginning, and then once she recovered from being born, she was eating way more frequently than that! I think it also matters how much they are eating at each feeding. Both of my kids could power down 4+ oz pretty much right from birth (I was nursing, but often pumped and had an oversupply of breastmilk anyway), so they needed to eat less often than little ones would would only take an ounce or two eat each feeding. If you're bottle feeding especially, you have a better sense of how much he's eating during the day. I would worry more about overall food consumption and less about how often it's happening.
As for the day/night thing, I think you've gotten good advice, but I just wanted to add that he'll be up a ton during the day soon enough, so if you have a preschooler to take care of, I would just let him sleep while you can! At this point, it's probably not impacting his nighttime sleep any. Good luck!