Think of your math numbers.
The Wii is still constrained by supply but it is still outselling the PS3 at least 3:1 without any game releases at all. I was just highballing the 5:1 figure considering that we don't know how high the actual demand is. I don't even know why you factored in the European numbers. I was talking talking about the Japanese market alone, probably the only market where a 5:1 Wii-PS3 ratio is likely to happen more than anywhere else.
FFXIII won't be a Wii exclusive. Square-Enix has already put a lot of work into a PS3 version, they're not going to just scrap that and start over.
I did say if the extraordinary selling power of the Wii over the PS3 continues. I wouldn't put it past SE to completely scrap a project if PS3 sales continue to stay at the 20k level, while the Wii can potentially to sell more than 100k a week(it isn't doing it now because of supply shortages).
After all, they would have nothing to lose to completely scrap a project and start on the Wii because its so cheap to develop on it, especially if the install base is overwhelming. I would think the profit margin is higher and would reach a wider audience in Japan. It is unprecedented, but so is the Wii.