What everyone else has said is right on the money :-)

The weight gain is a HUGE thing for nicu babies. I remember a gain of 10 grams in one day, although it doesn't sound like much - was a gain and a 'win' in my head; however in saying that if DD had gained 50 grams one day and 10 grams the next I'd be concerned big time. Nothing anyone could say could get that thought out of my head. So maybe be prepared for that kind of conversation - although it sounds like you already are.