ABX Company sent a sample of exporting goods to a German buyer during negotiation. Later, a contract was signed, and the provision of the goods was, “Moisture: 14%; Impurity: 4%.” Before shipment, the seller again cabled the buyer, “Quality as per sample”. After taking the delivery, the buyer had the goods inspected. Although the quality conformed to the terms of the contract, it was lower than that of the sample. As a result, the buyer filed a claim for compensation. Did the seller make any mistake? Why or why not?