A similar question has been answered a long time ago but, since November 2011, key pairs are now tied to the application itself, not to the account anymore.
My current application (first published in mid-2011) is still using the old account key for LVL verifications (but the application key for in-app purchases).
I'm considering moving that app to another account, but I'm not quite sure what I'm supposed to do with my LVL implementation (before moving): can I safely switch to the application key without caveats for my current customers?
From my understanding, there's nothing to do for in-app since I'm using the application key since the beggining.