Keep in mind that pumping output is never an indicator of baby's intake..diaper output is a good indicator, weight gain would vary for each baby and we would also have to consider their percentiles on the growth chart. If baby is otherwise happy and latching well, then there shouldnt be anything to worry about. For my 8mo, she gets distracted and unlatch all the time, so I'd know if she hasnt had enough when she gets whiny and unsettled.
You are doing great, mummy!