The Merchant agrees that higher compensation than that provided for in this Bill of Lading may not be claimed unless the nature and value of the Goods have been declared by the Merchant prior to the commencement of the carriage and inserted in this Bill of Lading in the space captioned "Declared Cargo Value" and extra freight paid on such declared value if required. In such case, the declared value if embodied in the Bill of Lading shall be the basis for calculating the Carrier's liability, (if any), provided that such declared value shall be prima facie evidence, but shall not be conclusive on the Carrier and further provided that such declared value does not exceed the true value of the Goods at destination. Any partial damage shall be adjusted pro rata on the basis of such declared value.