Confinement Nanny

My nanny has over 5 years of experience. In a year she does about 8 confinement. When my 2 wk old baby cries at night an hour or so after her last feed, she tells me she could still be hungry and tops up an additional 15-30ml formula. Is that right? Any mummies experience this too? She says it's based on her experience with many fussy babies at night