5 hours... Too long?

I am a new mom of premature triplets. They are now just over 2 months old and their due date is on Aug 29th. When they were in the NICU, they were feed every 3 hours. When we got home, we started feeding them every 4 hours. After 3 hours, we were struggling to wake them up to eat so we tried 4 hours and it has worked. Here's where I need some opinions. We have kept them on this 4 hour schedule even over night. Their ped said we don't need to do this overnight and have the babies wakes us when they are ready. We tried it last night and they would make it 4-5 hours between feedings. Well then we were tried to get them back on their 4 hour schedule during the day. We noticed, they were eating more and a lot faster when they were eating about 5 hours apart. Is changing the schedule to every 5 hours too long? Here are some other things to consider... 4 hour feedings... They are usually showing signs they are hungry. They will take anywhere between less than an ounce to 5 ounces, however it takes between 1-1.5 hours to feed 5 hour feedings... They were waking up before because they were hungry. They were eating 3-5 ounces but within 30-45 minutes. What would you do in this situation? Sorry for the novel. We just don't know what to do. Thanks!