(1)For the purposes of the formula in section 434(2) consideration for the disposal is brought into account—
(a)without any discount for postponement of the right to receive any part of it,
(b)in the first instance, without regard to a risk of any part of it being irrecoverable, and
(c)in the first instance, without regard to the right to receive any part of it being contingent.
(2)If—
(a)any part of the consideration so brought into account subsequently proves to be irrecoverable, and
(b)a claim is made,
such adjustment as is required in consequence must be made.
(3)An adjustment under subsection (2) may be made by way of discharge or repayment of tax or otherwise.