(1) All dues on or in respect of cargo are except as otherwise provided, to be computed on the weights and measurements shown in a vessel's manifest, bill of lading or other shipping document for such cargo.

(2) All such dues are to be computed on a weight basis or on a measurement basis (whichever computation produces the greater result) and if computed on a weight basis are to be computed on a tonne of 1 000 kilograms, and if on a volume basis are to be computed on a tonne of 1 cubic metre.

(3) A fraction of a tonne (by weight or measurement) is to be charged for on a pro rata basis.

(4) Dues are to be calculated on the gross weight or measurement but the Marine Manager may at any time demand that cargo is to be reweighed or remeasured in the presence of an officer of the Company and at the expense of the owner of the cargo in which event the weights or measurements ascertained from such reweighing or remeasurement prevail.