“Trends and variations Adjustments shall be made to the Gross profit Rate of Gross Profit Standard turnover and Annual Turnover as may be necessary to provide for the trend of Business and for variations in or other circumstances affecting the Business either before or after any of the Contingencies or which would have affected the Business had the Contingencies not occurred so that the adjusted figures shall represent as nearly as may be reasonably practicable the results which but for the Contingencies would have been obtained during the relative period after the Contingencies.”