Posted by: ark April 10, 2011
OPT Extension Urgent Please Help
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 Here is the case of one person: 
OPT expiry date: Oct 1
STEM applied: Sep 24
returned back for correction: Oct 2
sent after correction: Oct 4

Status: OPT got denied, 
Reason stated: Application received post the expiry date. 

So not sure what happens in ur case, could be lucky. 

I don't know which datet u mean by saying you applied for extension on time. USCIS recommends applying as early as possible (withing 3 months of expiry) so that something happens like this, you will have enough time to resubmit. 
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