Hi,
Something to discuss with your DSN is the possibility of using Levemir twice daily instead of once. Half a unit in the morning and half a unit at night will give a better, more even spread than the 1 unit dose that you were using previously, and it's also likely to stop the bedtime highs that you're seeing while using the single half unit dose.
I suspect that you're seeing the bedtime rises because the current single half unit dose isn't providing enough overlap with the next dose. Although a half unit split dose will put her back on a 1 unit total daily dose, the fact that the dose is split morning/night should minimise the hypo problem that you had previously while using the 1 unit total daily dose. Or at least that's the theory.
Good luck.