54.1.5. Except for a purpose contemplated in paragraph 1 of section 54.2, if a supply of property by way of sale is made to a lessee on the exercise by the lessee of an option to purchase the property provided for in an original leaseback agreement entered into by the lessee in respect of the property, or in a subsequent lease in respect of that agreement, to which section 54.1.1 applied, and immediately before the earliest time at which the consideration for the supply becomes due or is paid without having become due, there is an unused total purchase credit in respect of the property, the following rules apply:(1) the value of the consideration for the supply is deemed to be equal to the amount determined by the formula
A − B; and
(2) section 54.1.1 does not apply to any consideration that, after that earliest time, becomes due or is paid without having become due for any supply of the property by way of lease that was made under the original leaseback agreement or under a subsequent lease in respect of that agreement.
For the purposes of this formula,(1) A is the value of the consideration for the supply as otherwise determined; and
(2) B is that unused total purchase credit.