To be specific: If i have material purchased Qty 10 for $10 in June
2016, then in June I'd like to post my cost. In July, i sold out 2 pcs
for $1 Each. So my remaining inventory value at the end of July is $8.
In August, I paid a service $5 to cut the material. At the end of August
I my inventory value was $13.
For now, i am creating new fields to perform these calculations and i knew there MUST be a better way. Please help me. :(