Inventory working FIFO Method

I am looking for Inventory working on FIFO ( First In First Out) Method working formula in excel worksheet. I made worksheet based on Purchase Sale and Stock. but I am getting wrong valuation for stock in the formula i am using What i am looking for is, if i have purchased 100 (@ $1), 20 (@ $2), 30 (@ $3) units on day 1,2,3 respectivly and sold 50 units on day 4 then value of my stock of 100 units should be 50 (@ $1), 20 (@ $2), 30 (@ $3) $180 and not the weighted average of balance. also attached working sheet.