(2) The proportion of net tonnage referred to in sub-section (1) in respect of a previous year shall be calculated based on the average of net tonnage during that previous year.

(3) For the purposes of sub-section (2), the average of net tonnage shall be computed in such manner as may be prescribed in consultation with the Director-General of Shipping.

(4) Where the net tonnage of ships chartered in exceeds the limit under sub-section (1) during any previous year, the total income of such company in relation to that previous year shall be computed as if the option for tonnage tax scheme does not have effect for that previous year.

(5) Where the limit under sub-section (1) had exceeded in any two consecutive previous years, the option for tonnage tax scheme shall cease to have effect from the beginning of the previous year following the second consecutive previous year in which the limit had exceeded.

Explanation.—For the purposes of this section, the term "chartered in" shall exclude a ship chartered in by the company on bareboat charter-cum-demise terms.