CatBus said:

Differences that small are only really noticeable with lip sync (and barely noticeable at that).

Don't forget that the foreign language dubs contain more than just the voices... sound effects and music will still get out-of-sync ;) And I guess a 2 frame offset of a lightsaber hit sound might be noticable.

Anyway, for Empire DeEd I'm editing the German audio anyway (to add missing stuff and/or convert from lossless PCM to AC3), so I'll remove those 2 frames accordingly.