257. Where a registrant last acquired an immovable for use as capital property in commercial activities of the registrant and the registrant increases, at a particular time, the extent to which the immovable is used in commercial activities of the registrant, for the purpose of determining an input tax refund of the registrant, the registrant is deemed(1) to have received, immediately before the particular time, a supply of a portion of the immovable for use as capital property exclusively in commercial activities of the registrant; and
(2) except where the supply is an exempt supply, to have paid, at the particular time, tax in respect of the supply equal to the amount determined by the formula
For the purposes of this formula,(1) A is the lesser of(a) an amount equal to the total (in this section referred to as “the total tax charged in respect of the immovable”) of the tax that was or would, but for sections 75.1 and 80, have been payable by the registrant in respect of the last acquisition of the immovable by the registrant and the tax that was payable by the registrant in respect of improvements to the immovable acquired or brought into Québec by the registrant after the immovable was last so acquired, and
(b) an amount equal to the tax calculated on the fair market value of the immovable at the particular time;
(2) B is the extent, expressed as a percentage of the total use of the immovable by the registrant at the particular time, to which the registrant increased the use of the immovable in commercial activities of the registrant at the particular time; and
(3) C is(a) where the registrant was entitled to claim a rebate under sections 383 to 397 in respect of any tax included in the total tax charged in respect of the immovable, the difference between 100 % and the percentage prescribed for the purposes of section 386 or 386.1 that applied in determining the amount of that rebate, and
(b) in any other case, 100 %.