Formula feeding - how much at 6 weeks?

I am making 900 ml at a time, and putting 5 ounces into the bottles. My 6 week old son is eating almost all of it within 24 hours, if not more. He usually eats 4-5 ounces every 2.5 hours- 3 hours. Is this a lot or is he just on the higher end of normal??? Sometimes he is even hungry at the 2 hour mark, but I try to make him wait a little bit by using a pacifier.