I don't think you can generalize and say that there is an edge there. moc prints are very inconsistent and its probably a 50/50, not to mention that you won't be able to cancel the order during the last 20 minutes if the market turns on you. Maybe I'm just bitter from having seen a few too many "can't miss" moc prints gap against me. Maybe you should try tracking the moc vs. where you exited for a period of time and find out whether you would have benefitted.