16.—(1) If during the construction of a specified work or during a period of 24 months after the completion of a specified work any alterations or additions, either permanent or temporary, to a dock area are reasonably necessary in consequence of the construction of the specified work in order to avoid detriment, and the Board gives to DLRL reasonable notice of its intention to carry out such alterations or additions (which shall be specified in the notice), DLRL shall pay to the Board the reasonable cost of those alterations or additions including, in respect of any such alterations and additions as are to be permanent, a capitalised sum representing the increase of the costs which may be expected to be reasonably incurred by the Board in maintaining, working and, when necessary, renewing any such alterations or additions.
(2) If the cost of maintaining, working or renewing a dock area is reduced in consequence of any such alterations or additions a capitalised sum representing such saving shall be set off against any sum payable by DLRL to the Board under this paragraph.