This section applies where a person who makes a claim under this Chapter, acting in the same capacity as that in which he makes the claim—
sells an interest to which section 191(1) would apply but for section 191(3), or
within the period of three years immediately following the date of the death exchanges (with or without any payment by way of equality of exchange) any interest in land which was comprised in the deceased's estate immediately before his death.
and the sale price of the interest, or in the case of an exchange its market value at the date of the exchange, exceeds its value on death.
Where this section applies, an addition shall be made to the sale price of any interest to which the claim relates; and the amount of the addition—
if the claim relates to one interest only, shall be equal to the excess referred to in subsection (1) above, and
if the claim relates to more than one interest, shall be equal to the appropriate fraction of that excess.
In subsection (2) above "the appropriate fraction" in relation to any interest to which the claim relates is the fraction of which—
the numerator is the difference between the value on death of that interest and its sale price (as adjusted under sections 193 to 195 above) and
the denominator is the aggregate of that difference and the corresponding differences for all the other interests to which the claim relates;
and the aggregate referred to in paragraph (b) above shall be calculated without regard to which is the greater, in the case of any particular interest, of its value on death and its sale price.