21. For the purposes of determining the median proportion for the first fiscal period to which a roll applies where that roll, according to the assessor of the municipal body responsible for the assessment that caused the roll to be drawn up, is the result of an equilibration within the meaning of the third paragraph of section 46.1 of the Act respecting municipal taxation (chapter F-2.1), the following operations shall be performed consecutively:(1) the number of sales entered on the basic list is divided by the number of sales to be entered on the list, and the quotient thereby obtained must comprise 2 decimals;
(2) the quotient resulting the division prescribed in subparagraph 1 is multiplied by the median ratio determined under section 18;
(3) the number of sales entered on the basic list is subtracted from the number of sales to be entered on the list;
(4) the difference resulting from the subtraction prescribed in subparagraph 3 is divided by the number of sales to be entered on the basic list, and the quotient thereby obtained must comprise 2 decimals and be transformed into a percentage;
(5) the product resulting from the multiplication prescribed in subparagraph 2 and the quotient resulting from the division prescribed in subparagraph 4 are added together.
In the operation prescribed in subparagraph 2 of the first paragraph, the number representing the median ratio is used without taking into account the fact that it is a percentage; the result of that operation is, nevertheless, a percentage.