Subject to the provisions of this section and of section 138 of this Act, in this Part of this Act—
In the case of a claim holding where—
the amount of any such fraction as is referred to in subsection (1)(b) of this section shall be treated as reduced proportionately.
In the case of a claim holding where—
the amount of any such fraction as is referred to in subsection (1)(b) of this section shall be treated as reduced, or (as the case may be) increased, proportionately.
For the purposes of this section, the part of the amount of the relevant established claim which was properly attributable to any land forming part of the claim area shall be taken to have been so much of the amount of that claim as might reasonably be expected to have been attributed to that land if the authority determining that amount had been required to apportion it, in accordance with the same principles as applied to its determination, between that land and the residue of the claim area.