There is no warning or way of knowing when transferring a BOM if the parts are being taken from the BOM or from the sub-components of said BOM. There should be a warning to alert the user to a 'sub-component' transfer. Additionally it would be useful to have a direct and sub-component transfer quantities available when viewing the BOM, as this also causes confusion when the sub-components require further processes to create the finished article, for example a casting that requires machining.