Graendal cannot comment later that she killed Asmodean if she is dead by balefire.

There is a theory out there that we might see Asmodean reappear in the series, based on the assumption that Graendal could have been burnt out far enough back to undo Asmodean's death.

The logic goes like this:

1. No character has yet revealed themselves as Asmodean's killer.
2. Graendal cannot reveal herself as Asmodean's killer because she died by balefire.
3. The only possible way to still implicate Graendal as Asmodean's killer is if somehow Asmodean were to reappear in the series (i.e. if Graendal were the killer and she was balefired back far enough, then Asmo might reappear)
4. Because Brandon says it is impossible to burn Graendal out that far back, it is impossible the balefiring of Graendal will cause Asmodean to reappear.
5. Graendal cannot reveal herself as Asmodean's killer directly (because she is balefired) or indirectly (by Asmodean reappearing).

Ergo, somebody else killed Asmodean, not Graendal.