In any case where, apart from this section, the loss on sale of any investments—
(a)in respect of which an amount has been paid in pursuance of a call as mentioned in section 182 above, or
(b)which are sold as mentioned in section 183(5) above,
would exceed their value as determined apart from this Chapter, their sale value shall be treated for the purposes of sections 179(2) and 187 above as being of such an amount that the loss on sale would be equal to their value as so determined.