I was not talking about importing assembly items, that works with all the importers I have tested.

The "Build Assembly" function you need if you buy in bulk but sell in small package sizes. In our case we buy all our products in bulk (kilo, lbs), then repackage it to small bags in 2, 4, 8, 16oz. To adjust the bulk and the packaged inventory correctly, you use the Build Assembly function in QB.

When I download all our sales transactions from our web-site, I run several VBA to create the sales receipts, the builds assemblies, and payment fees, then use our Business Importer to import everything into QB.

This works fine and fast. I just would wish that the Business Importer has a more intuitive front-end after loading the Excel data, but my processes work.