Hi Hilmar

>This question is more about how inventory is handled in actual practice - not about how to program it in a specific language.

Dragan's second point is something I have implemented and agree with. The client is first supposed to decide what the basic unit of stock is, say "numbers". Then in the items master you have a grid in which they can put in the various packings and their conversion to "numbers", for eg. "Box of 10", with "Multiply", 10 as the conversion unit, "Box of 25" with "Multiply", 25, "Bag" with "Multiply", 100. So when you do a transaction you get the item name "Screw" and a selection from "Box of 10", "Box of 25", "Bag", when you caculate the stock you apply the conversion to the qty and you have your basic unit numbers to report on. This is for a conversion of multiples, you can go the other way too, so I ask the user when they are putting in the conversion if it is a multiply or divided.