(1) When it appears to the Board that any development or improvement scheme is sufficiently advanced to enable the amount of the betterment tax to be determined, the Board may, by an order made in this behalf, declare that for the purpose of determining the betterment tax the execution of the scheme shall be deemed to have been completed and shall thereupon give notice in writing to the owner of the property or any person having an interest therein that the Board proposes to assess the amount of the betterment tax in respect of the property under section 19.
(2) The Board shall then assess the amount of betterment tax payable by the person concerned after giving such person an opportunity of being heard and such person shall, within sixty days from the date of receipt of the notice in writing of such assessment from the Board, inform the Board in writing whether or not he accepts the assessment.
(3) When the assessment proposed by the Board is accepted by the person concerned within the period specified in sub-section (2) such assessment shall be final.
(4) If the person concerned does not accept the assessment or fails to give the Board the information required by sub-section (2) within the period specified therein the Board shall make a reference to the District Court for determining the betterment tax payable by such person.