I have a suggestion, that when you beat the boss of the OMm your time gets recorded. Time= first entering the dungeon-beating the boss. Then, at the end of the week, the top 10% fastest time in pool A would get the OM, and the top 1% in pool b would get the OM. This would be much more functional, as it would be based off skill, and not free time. I’ve heard too many people complain about finishing late, and this would make it so that they could only think to themselves," I need to find a better strategy or better arks to get the OM." Just a suggestion.
It’s been suggested before, I believe.
Really? I didn’t even read that…
Great idea, I am always busy
Yes, been suggested already 
But good idea though~^^
I actually thought it was already implemented because , i think Jasonology (though i could be wrong), was in pool B and got the OM reward after started doing the mission 11 hours after the OM start time. And someone else started 3.5 hours after the mission start time. A great explanation for that phenomenon would be that Jasonology must have breezed through the mission in record time.