Seems off. I used a higher income with sibling and it estimated $13k family contribution via IM formula. That was close to BU’s own calculator, which suggested a $17k combination of loans and family contributions, forgiving roughly $60k via needs.
FM estimated twice IM which I take to mean BU uses IM.
Your link asks if you want Federal or Institutional Method when calculating expected family contribution (FM vs IM) or to run both methods. I don’t know why a school would choose one or the other, just noting the similar result from IM.
FM estimated twice IM which I take to mean BU uses IM.