1.1. For the purposes of this Act, where an immovable constitutes, at the time of its transfer, a unit of assessment entered on the real estate assessment roll of a municipality or part of such a unit the value of which is separately entered on the roll, its market value shall be the product obtained by multiplying the value entered on the roll for the unit or part corresponding to the transferred immovable, as the case may be, by the factor of the roll established in accordance with section 264 of the Act respecting municipal taxation (chapter F-2.1).