Sum of Cost in TransactionEntry table

I just need to verify this. I just discovered that if you Sum(Cost) in TransactionEntry table, it only sums up the cost of each item in each transaction. But if you sell qty of, say, 2 of the same item in a single transaction, the Cost column only shows the cost of 1 qty. Thus to get the right cost, you have to do Cost*Quantity. Is this right?