I do not feel that the following dialog:

"How did you destroy all but a remnant of the Dark Lord?"

Harry hesitated. "I Obliviated most of his memories and... sealed him, I guess is how wizards say it. Even if the seal breaks, he won't come back as himself."

Severus frowned briefly and then shrugged. "I suppose that is acceptable."

really fit with what Snape told sooner in the story:

"No," Severus said flatly. "The prophecy is not yet fulfilled. I would know if it were."

"Are you sure of that?"

"Yes, Potter. If the prophecy had already come true, I would understand it! I heard Trelawney's words, I remember Trelawney's voice, and if I knew the events that matched the prophecy, I would recognize them. What has already happened... does not fit." The Potions Master spoke with certainty.

I was expecting a more interesting reaction than just a shrug from Snape.