formula feeding - amounts 1 month old

I was so set on breast feeding, but my milk never came in. So we are on formula now. He is doing very well, but seems hungry so much! He is a month old tomorrow, and he's taking 4 ounces at a feed, usually would take more. Not screaming for more, but he will still reach for the bottle once it's empty. I was told every four hours would be good, but he is crying to eat again at three hours on the dot normally. So he eats anywhere from every 3-4 hours, 4 ounces. I've started giving him 5 ounces at night and he seems to be doing well, but I'm not sure if I should go ahead and up his daytime bottles to 5 ounces. And I'm not sure if it will increase the time between his feedings or not - or if I should be worried about that right now. Distracting him with play or his pacifier works for a few minutes, but not log periods. Any input or advice would be appreciated!!