When should pumping output go up?

Vegasbb

Mobile: When should pumping output go up?

As in, as my LO gets older, shouldn't I be leaving bigger bottles for him so shouldn't my pumping output go up? Since LO was born, I've only been able to get approximately 1 ounce per hour (ie if I go 3 hours without feeding him, I get 3 ounces. If I go 2 hours, I get 2 ounces). From doing weighed feedings, this lines up with about what he's taking in (he seems to eat 2 ounces every 2 hours during weighed feedings). 

I know 24 ounces is on the low end of what breastfed babies should be taking in per day. Also, I was under the impression at some age (is this age 2 months? 3 months? 4 months?) they start eating more than they do as a newborn. My LO is 14 weeks (sorry no siggy). At what point should he be eating more? I worry because my pump output isn't changing, but I fear when I leave him I should be leaving more than just 2 ounces in a bottle for every 2 hours.