If the IAA interviews an applicant, it might them form an impression of the demeanour of the applicant. This impression is ‘new information’ and attracts the obligation to invite comment, under s 473DE. In ABT17 v Minister for Immigration and Border Protection  HCA 34 at  the plurality said:
... The Authority's own visual impression of the referred applicant's appearance during such an interview would necessarily constitute new information within the power of the Authority to get because it would communicate knowledge of an evidentiary nature which would be open to be considered by the Authority to have the potential to bear on the Authority's assessment of the referred applicant's credibility and which was not before the Minister when the delegate made the referred decision.
See also :
Were some aspect of the referred applicant's appearance during the interview to end up being so glaringly undermining of the referred applicant's credibility as to lead the Authority to consider in advance of reasoning on the facts that the appearance of itself "would", as distinct from "might", be the reason or part of the reason for affirming the decision of the delegate, the Authority would come under an obligation to explain that to the referred applicant and to invite the referred applicant to comment. ...
By parity of reasoning, the IAA’s impression it forms based on observations it makes from listening to or watching a recording should also be ‘new information’, because these impressions are also ‘knowledge of an evidentiary nature’.
Hence, it is unreasonable if the IAA ():
... without good reason, ... does not invite a referred applicant to an interview in order to gauge his or her demeanour for itself before it decides to reject an account given by the referred applicant in an audio recorded interview which the delegate accepted in making the referred decision wholly or substantially on the basis of its own assessment of the manner in which that account was given.