In automotive it is pretty much a standard requirement to have all Your items (both purchased and produced) listed in the IMDS (International Material Data System). To make it easier for You to find Your parts in the system You
Why do I see also purchased items when creating a sales order?
Because You can sell anything. For example if you intermediate a purchased item it would be unreasonable of Petkafy to block you from creating a sales order with such item number. Then You would probably create another item and add