(1) Any depreciation allowed under this Act which cannot be fully charged as an expense against the gross profit of any assessment year, it shall be added to the depreciation of the next assessment year.

(2) Any disallowance of depreciation allowance on account of failure to comply with any provision of this Act shall not be carried forward.

(3) Before charging the carried forward depreciation allowance the carried forward loss shall be set off.

(4) Allowed depreciation allowance may be carried forward until wholly set off.