The Illinois Administrative Procedure Act is hereby expressly adopted and shall apply to all administrative rules and procedures of the Department of Revenue under this Act, except that (1) paragraph (b) of Section 5-10 of the Illinois Administrative Procedure Act does not apply to final orders, decisions and opinions of the Department, (2) subparagraph (a)2 of Section 5-10 of the Illinois Administrative Procedure Act does not apply to forms established by the Department for use under this Act, and (3) the provisions of Section 10-45 of the Illinois Administrative Procedure Act regarding proposals for decision are excluded and not applicable to the Department under this Act to the extent Section 10-45 applies to hearings not otherwise delegated to the Illinois Independent Tax Tribunal.