In Half Blood Prince, Dumbledore tells Harry that:
"The seventh part of his soul, however maimed, resides inside his regenerated body. That was the part of him that lived a spectral existence for so many years during his exile; without that, he has no self at all. That seventh piece of soul will be the last that anybody wishing to kill Voldemort must attack — the piece that lives in his body.”
— Half Blood Prince, Chapter 23, Horcruxes.
Why does the master piece that lives in Voldemort have to be the last?
If Voldemort was killed* in the usual way (as he was in 1981), i.e., this master piece was ripped of his body and then all his Horcruxes were destroyed, would he not be finished for ever, and meet the same fate in eternal limbo as he did at the end of Deathly Hallows?
The natural answer seems to be affirmative, if not for the fact that Dumbledore explicitly uses the word 'last'.
If no, what would happen in the alternate scenario described above?
I vaguely remember some mention of this problem in this site, but it could have been in the comments.
*I must clarify that 'kill' here must refer to ripping the (part of his) soul in his body, allowing for the possibility that he might regenerate, as opposed to the ordinary usage of the word 'kill', which leads to death for unhorcruxed people.