A Sales Order for a finished good or work in progress would check to see if any were available. If none or only some were available then it would automatically create an Assembly Order.

Now, the process checks not only what is available (i.e. what is on the shelf), but also if any existing Assembly Orders are making that SKU and of those quantity being made, how many are available (in other words, how many are not on backorder).

This reduces unnecessary Assembly Orders and an unintended build up of stock.