My current L1B visa and I94 both expiring on Sep 23rd, 2016. My company is ready to file extension petition on premium processing now.But our attorney says we can start the filing on Sep 1st week so while the petition is in process i can continue staying in US for 240 days.If the immediate premium request is rejected, i will have to leave US immediately. Is that correct, or i can stay in us until my I 94 validity i.e.Sep 23rd in case my current petition is denied?