How come when you sum (D9:D19), your expert answer saids NPV is -3620 (Which is the right answer on my question), however, no matter how many times I sum up (D9:D19), it is off by one, calculating at -3621. I had another question where the same thing is going on... I also posted the picture of the expert answer of the other question. I sum up the present value row and the answer is off by one or two. What am I missing? That is basic addition. How come your answer is -3620 when the numbers added up in the last column is actually -3621? And on the second example, the present value column really adds up to 49,618, not 49,620..... Where did the extra 2 come from????

Project A Present value of Inflows 543,280 Profitability Index =$543280/493660= 1.10