Feeding your 4 week old

Just last week my daughter was having 2oz of formula every 3-4 hours we just upped it to 3oz every 3-4 hours because she was wanting more. During the night we let her sleep and wake up for feedings and it’s closer to every 4 hours. Her pediatrician said don’t wake her and let her tell you when she’s hungry. Around 6-8pm she falls asleep and goes into deep sleep where she won’t wake up after 4 hours for her feeding. I usually change to diaper to see if she will wake.. what do you ladies do/recommend? Should I wait till she wakes up even when it’s past the 4 hours or should I try to wake her?