Lesser milk consumption

6 weeks na ng baby ko and before 3oz kaya niyang ubusin and now biglang bumaba consumption niya into 2 oz tapos natutulugan na niya yung feeding bottle niya. Pero nagigising naman siya every 2 hours at uubusin niya yung 2 oz ulit. Normal ba ito mga mamsh? Nabasa ko kasi online na dapat consumption na ni baby is 4 oz at every 4 hours na feeding. Should I change yung tsupon niya kasi yung pang-newborn pa gamit ko at maliit yung butas