Is there a formula that will deduct an amount from a total in one column but when it reaches zero, the remaining amount gets deducted from another column so that there is not a negative amount showing. For example. There are 3 items left from the first stock order (column 1) and 20 items left from a the second stock order (column 2). A client as for delivery of 10 pieces of the item. 3 out of the 10 pieces get deducted from the first stock order, bringing the total to zero, no more stock left (column 1) and the remaining 7 items get deducted from the second stock order (column 2).