(6)The appellant shall not, except by leave of the State Commission urge or be heard in support of any ground of objection not set forth in the memorandum but the State Commission, in deciding the appeal, shall not confine to the grounds of objection set forth in the memorandum or taken by the leave of the State Commission under this rule.Provided that the commission shall not rest its decision on any other ground unless the party who may be affected thereby, has been given, at least one opportunity of being heard by the State Commission.
