We've been preparing this weekend for the tourney, and we might not have a chance to prepare again together during the week cause not everybody is available on week days.
We planned our strategies based on how the IA responds right now, so if you change the way the IA is playing this week, all our work will be useless, and we might have no time to test again how the IA is working.
It's like changing rules : if you say two days before the tourney that it's not full share anymore, it will be very annoying.
Not that my team and I are tryharding for the victory, but I think it's a general good habit when organizing a tourney to have at least 1-2 weeks without any update to the game before the tourney