Hmm. The timeline I was assuming for my previous post:
Late 1979 until spring 1980: Prophecy. On that night Severus was merely hanging out at The Hog's Head. If there was a plan for him to apply for the DADA job it was derailed by the prophecy.
Late 1980 or early 1981: Hilltop meeting.
Summer 1981: Voldemort sending Severus to apply for DADA and serve as his spy.
Since by the time of the 1981 interview Voldemort might have thought Dumbledore might have already suspected Severus, he could have tried sending him under the cover of repentant DE, not knowing he already repented.
Late 1979 until spring 1980: Prophecy. On that night Severus was merely hanging out at The Hog's Head. If there was a plan for him to apply for the DADA job it was derailed by the prophecy.
Late 1980 or early 1981: Hilltop meeting.
Summer 1981: Voldemort sending Severus to apply for DADA and serve as his spy.
Since by the time of the 1981 interview Voldemort might have thought Dumbledore might have already suspected Severus, he could have tried sending him under the cover of repentant DE, not knowing he already repented.