Well... couple points: (Please, do read down to #3, even though 1&2 may tick you off)
1) My 3 week old son was drinking apx 20oz (TWENTY, yes, not a typo) PER feeding every 2-3 hours. (We were part of a breastfeeding study). He was 10lbs at birth and 12 or 13 by week 3. Some full term newborn infants can only manage an ounce or 2, most can do between 3 & 8. A couple ounces is the bare MIN. So when you start off on the basis that in order to live/ not be 'failure to thrive' you need at least that much (80ml) and can go up to 10-20oz per feeding... that's a "Relax..." set of numbers... not necessarily a 3mo feeding schedule. 60-80ml is a preemie bare minimum goal (4-5lbs). A healthy 10lb newborn usually goes for over 200ml.
2) NICU babies -even full term- tend not to eat well for a couple reasons. A: they're stressed out, and the increased adrenaline, just like in adults, shuts down the hunger response. Well... they still need the nutrients to be healthy. Unlike with an (most) adult patients, with NICU & PICU patients you can't tell them "I know you're not hungry, but you need to eat anyway." Instead you NG them, and work toward getting them eating the bare minimum even under the huge amount of stress they're under. B: Babies tend to be in the NICU for a reason that makes them tired. They're using every bit of available energy to heal/recover and the physical act of sucking and swallowing is just too much. So even if they ARE hungry, they turn and refuse to eat more because they're just too tired.
3) As to how much sway a parent has... QUITE a lot, to a certain point. You're there 24/7, and most good NICUs consider (and even title) parents as "Parent Caregivers". Parents tend to notice things first, and hold onto all the little bits of info from the course of the day in their minds, only have 1 patient, and aren't taking notes from a previous shift. MOST NICUs consider you part of the team with a full 'vote' in your child's care. There is, however, a VERY steep learning curve... and a lot of sleep dep. The line at which parents are disregarded is in 2 places: a) when it will cause the child harm without question and b) when they are completely and totally distraught/furious/losing it. If you're completely emotional, staff assumes (mostly correctly) that you're not thinking clearly and at the VERY least need a break, a sleep, or an eat... and most will flat out refuse to listen to a word you say until you're able to calm down and present your thoughts clearly. Even if that's just an "I can't think right now, can I have a little bit of time to process, and we can revisit this in a few hours?"
4) 2nd opinions are common. If you're not at the regional children's hospital, grab your 2nd opinion from THEM. If you are, then you've got the hands down best staff available in 3 states... so jump departments.
Hugs!!! Handsome little guy!