hey actaully i had similar situation. couple weeks ago i went to local INS for EAD renewal( per what i told i should go 3months before my current one expires)
and the officer in INS said why u came over here ur EAD is still vaild till Feb. 2006 i said i was told to come 3 months in adavance. and she told me nope just come over when it expires. MEANWHILE she said:
anyway dont bother even it is expired if ur employee doesnt care about that.we dont care at all.
from what she said i dont think that will be a big issue