Hi Andrew
How about if the Stock Transfer is from one item to another, and the one being transferred from is using Standard costing?
I would not have intuited that an assembly ignores the costing method of the components - I guess I'm OK with it but I think it should be noted somewhere. The workaround is to have the master item use Standard costing, and enter as its standard cost the sum of the standard costs of the components. This will only be a problem if the master item has multiple bills of material, or if it is also purchased outright. However, it will be harder to maintain the proper standard cost when component costs change.
Steve