As I know Odoo maintains the FIFO inventory by making stock quants .
e.g : If we receive 5 balls for $5 then it makes one quant.And then for 2nd quant 3 balls cost 1.25$ each. Now when we make SO and delivery of 7 balls, it will took 5 balls@5$ from 1st quant and 2 balls @1.25*2=2.5  from 2nd quant and total cost of the stock move is 5+2.5=7.5.

Now how we can see that which quants and costs are being used in delivery orders's stock moves which are done?