Do NEC drives support bitsetting, also known as booktype modification?
Official NEC branded firmware generally only supports DVD-ROM bitsetting for DVD+R DL discs. For single layer DVD+R and DVD+RW bitsetting, you will need to flash to an OEM firmware (such as an HP or Mad Dog fw) or a modified firmware with bitsetting support added in. Check the NEC forum for details on specific firmware versions and their bitsetting capabilities.