3. (1) In 1994, the treasurer shall establish, (a) a realty tax differential for each separately assessed residential or farm property in the special area by calculating the product of 301.341 mills and the assessment on that property as shown on the last returned assessment roll for the City of London prepared in accordance with subsection 46 (3) of the Act, and subtracting the 1993 residential tax responsibility on that property; (b) a realty tax differential for each separately assessed commercial or industrial property in the special area by calculating the product of 354.519 mills and the assessment on that property as shown on the last returned assessment roll for the City of London prepared in accordance with subsection 46 (3) of the Act, and subtracting the 1993 commercial tax responsibility on that property; and (c) a business tax differential for each separately assessed business in the special area by calculating the product of 354.519 mills and the commercial assessment for that business as shown on the last returned assessment roll for the City of London prepared in accordance with subsection 46 (3) of the Act, and subtracting the 1993 business tax responsibility on that business. (2) If, before the return of the assessment roll for purposes of taxation in 2004, the assessment pertaining to a residential or farm property in the special area is reduced from that shown in the assessment roll for the City of London as prepared in accordance with subsection 46 (3) of the Act, the treasurer shall re-establish the realty tax differential under clause (1) (a) and, for this purpose, the reduced assessment shall be deemed to be the assessment shown on the 1994 assessment roll for the City of London prepared in accordance with subsection 46 (3) of the Act. (3) If, before the return of the assessment roll for purposes of taxation in 1998, the assessment pertaining to a commercial or industrial property or a business in the special area is reduced from that shown in the assessment roll for the City of London as prepared in accordance with subsection 46 (3) of the Act, the treasurer shall re-establish the realty tax differential under clause (1) (b) or the business tax differential under clause (1) (c), as the case may be, and for this purpose the reduced assessment shall be deemed to be the assessment shown on the 1994 assessment roll for the City of London prepared in accordance with subsection 46 (3) of the Act. O. Reg. 291/94, s. 3 (1-3). (4) If, before December 31, 1996, as a result of an assessment appeal under the Assessment Act, the assessment pertaining to a residential or farm property, a commercial or industrial property or a business in the special area is adjusted from that shown in the last returned assessment roll for the City of London for the purposes of taxation in 1993, the treasurer shall re-establish the realty tax differential under clause (1) (a) or (b), or the business tax differential under clause (1) (c), as the case may be, and for this purpose the adjusted assessment shall be deemed to be the assessment on the last revised assessment roll of the City of London for the purposes of the interim tax levy in 1994 under section 156 of the Municipal Act. O. Reg. 291/94, s. 3 (4); O. Reg. 818/94, s. 3. (5) A tax differential re-established under subsection (1) in accordance with subsection (2) or (3) shall be used to determine the amount of tax assistance to be provided under subsection 5 (3) or (4), as the case may be, commencing on the effective date the change is made to the last returned assessment roll. (6) A tax differential re-established under subsection (1) in accordance with subsection (4) shall be used to determine the amount of tax assistance to be provided in any year under subsection 5 (3) or (4), as the case may be. O. Reg. 291/94, s. 3 (5, 6).