2 week old baby

I usually just feed my baby when she's hungry at night but sometimes she's not hungry for like 4 hours; she'll eat, burp, pee, cry which takes an hour and then fall asleep for another 3 hours or so. She's formula fed 3 oz. Is it ok that she's not hungry every 2-3 hours sometimes? I know that's how often I'm supposed to feed her but if she's sound asleep I don't see why I need to wake her up when she'll wake up in an hour or two because she's hungry anyway.