8che, you"re on! ..."the point when an aircraft begins to move under its own power for the purpose of preparing for take-off, after that point- QRH only." It means- if you are on the RW and start moving for T/O. Sure, if you taxi to the RW and EICAS messages appears, NNCL first, MEL second, decision third. But if you start moving on the RW for T/O purpose, QRH- first and later you CAN use MEL, but for reference only.