how many ounces does your 8 week old drink a day

Shayron
My baby is 8 weeks . He drinks about 20-22 ounces a day . I know they're supposed to drink their weight times 2.5 which would be about 27 ounces daily for him. But I'm
Not concerned as he's gaining and flourishing . However I want to know does anyone else have little ones who only eat a little .