(5)Where, in exercise of the powers conferred by sub-clause (iii) of clause (c) of sub-section (2) of section 103, the terms of an existing permit are modified so as to curtail the area or route of any vehicle authorised to be used thereunder, the compensation payable to the holder of the permit on account of such curtailment shall be an amount computed in accordance with the following formula, namely:YxARExplanation. In this formula,(i)Y means the length or area by which the route or area covered by the permit is curtailed;(ii)A means the amount computed in accordance with sub-section (4);(iii)R means the total length of the route or the total area covered by the permit.