On an application for review of a reviewable objection decision:
(a) the applicant is, unless the Tribunal orders otherwise, limited to the grounds stated in the taxation objection to which the decision relates; and
(b) the applicant has the burden of proving:
(i) if the taxation decision concerned is an assessment--that the assessment is excessive or otherwise incorrect and what the assessment should have been; or
(ii) in any other case--that the taxation decision concerned should not have been made or should have been made differently.