At one time the Pontifical Biblical Commission was essentially a low-ranking Congregation. Its decisions, though, were not considered to be dogmatic or doctrinal. Its directives were neither infallible nor unchangeable. Its decisions could be officially challenged by theologians and clergy through proper channels.
At that time, the weight of its documents would have been the equivalent of the “official opinion of the Church.” Given that these official opinions were policy and not doctrine, newer statements by the Commission or Magisterium superseded any previous statements by the Commission.
Paul VI, however, changed the Commission from a low-ranking Congregation to a simple commission of scholars who issue statements on the latest in scriptural studies. Today it carries only the weight of the respect of the opinion of its members.