I think the timing was absolutely intentional and carefully worked out. In theory there were enough hours in the 7 days but you would have to be playing 24 hours a day to put the quests in etc.
The last 3 events in Farm Story 2 have shifted into events where you really need to buy gems to get the prizes. I was expecting to see this roll out to more games.....so I am not surprised to see it in DS.