In a perfect world, if everyone updates their approval in rupnet.com on the same day as their AD, the system can be said perfect system and we would get a perfect answer...!
But in reality, Since most people DON'T update on the same day of approval[Understandable enough - coming to know of approval later, or not just bothering to check regularly, or in cloud9 on AD], update rupnet.com after AD and if the query is against AD, then these cases would be missed out..!
So I guess query on last updated date is the solution