If the grant of a patent is opposed, the Commissioner must—
(a) give the applicant and the opponent a reasonable opportunity to be heard before deciding a case; and
(b) consider whether any of the following grounds are established on the balance of probabilities:
(i) any ground set out in section 87A that is relied upon by the opponent:
(ii) any other ground set out in section 87A that the Commissioner has decided to take into account (whether relied upon by the opponent or not); and
(c) otherwise decide and deal with the case in the prescribed manner.