I have a lookup table that lists the monetary cost of certain items. However, I have now been told the costs are to increase, but only items entered after 1st April should use the new price in the calculations. A simplified example would be: in March I bought 5 apples at 10 pence each = 50p. In April each apple will cost 12 pence, so the overall cost of 5 apples will be 60 pence but I want my table to show 50p for the March entry and 60p for the April entry. How can I change the individual item costs in the lookup table without making the apples I bought in March 60p? Can anyone suggest a solution? As costs may be increased a few times each year I need something I can roll on for each increase.