Fan consensus is that if Hermione’s claim in chapter 9 of Deathly Hallows is not a continuity error, then it means that she was wiping the two Death Eaters’ recent memories rather than modifying them. The relevant block of text, conveniently using the word "wiping" is as follows:

"We just need to wipe their memories," said Harry. "It’s better like that, it’ll throw them off the scent. If we killed them it’d be obvious we were here."
"You’re the boss," said Ron, sounding profoundly relieved. "But I’ve never done a Memory Charm."
"Nor have I," said Hermione, "but I know the theory."
She took a deep, calming breath, then pointed her wand at Dolohov’s forehead and said, "Obliviate."
At once, Dolohov’s eyes became unfocused and dreamy.

By taking this action, the trio are making some assumptions that I find questionable:

1. Rather than use a spell that she is so skilled in that she successfully used it to radically change her parents’ memories and life ambitions, it is better for Hermione to use a spell that she has never used before. The idea that she may botch the spell, putting everyone’s life at risk either immediately or as soon as the Death Eaters wake up, is not considered.
2. Wiping the memories of these Death Eaters is somehow a better choice than editing said memories to make them think that they found nothing, found the wrong people, or that they attacked each other.
3. The Death Eaters, upon waking up and having no idea how they got to where they are, will not suspect that they found their target and lost the battle.
4. The trio, despite having access to teleportation, extra-dimensional storage, and the ability to reduce objects to a fine powder, are incapable of making it non-obvious that they’ve killed someone.

So why did they act in this way? Surely, the better move was to modify the Death Eaters’ memories rather than wipe them? I can understand point #4 being rejected on moral grounds, but the other three assumptions cause me great confusion.