Buyer has the option, at his expense, to request for joint sampling and sealing, advising the Seller in due time the name of the Independent Surveyor he is appointing. If the difference of any of the following items between Buyer and Seller certificates does not exceed the below mentioned percentages, then the Seller's results will be final. Otherwise, at request of either party at his expenses, within 45 days from the B/L date, a third test shall be carried out by a mutually agreed Independent Laboratory. The average of the 2 closest analysis results shall be final under this contract, and must be settled by a complementary debit note.