" Hi, we are about to set up a manufacturing process for a customer for their OEM products.

We invoiced them for bulk production with different items (auto-build items) we sold.
Then, we packaging the product into two different sizes of bags.
We need to bill the customers for the bulk production in kilograms.
then, bill them for each bag of packaging & labeling.
In the end, we provide drop shipping service from those custom-made end products in different sizes.
We need to have stock control on those end products, provide regular stock reports and inform customers when the minimum stock alerts.
We already billed customers for the bulk productions in kilograms of each variety, but once they paid the bill and we don't hold the sock anymore, can not auto-build the item into different size of the end product. How should we do it in the process?"