Is it permissible for a Muslim who has prayed Witr after Isha as a precautionary measure to pray it a second time when performing night vigil (Qiyam al-Layl) at a later hour?

Whoever prays Witr with the 'Isha prayer, there is no harm in it, and whoever delays it until the last part of the night, there is no harm in it either. And whoever fears that he will not wake up in the last part of the night, let him pray Witr at the beginning of it. And whoever hopes to wake up in the last part of the night, let him pray Witr at the end of the night, because prayer at the end of the night is witnessed and superior. If one prays Witr at the beginning of the night and then wakes up, he may pray Tahajjud and not pray Witr again, and this is the opinion of the majority of scholars. There is another opinion that permits him to pray one rak'ah to negate the Witr, then pray Tahajjud and pray Witr at the end of his prayer.