It's called PS4 undertracking, not no reason. XB1 did not win that week.

So to quote ioi from the 27 Sept Sales thread http://gamrconnect.vgchartz.com/thread.php?id=191302&page=3 :

"We're estimating about 70k or so for the first week based on some XBL analytics (applying similar useage ratios as in other Asian countries) but clearly this has a fair margin of error. I'd say somewhere between 50 and 80k would be a reasonable range for China week one but there will be a big dropoff."

The gap for 27 Sept week is 65K. I think China needs to be a minimum of 80K for Xb one to to be likely to win China week. Because Xb one had the Fifa bundle boost I expect Xb one to drop off somewhat more than PS4 in the rest of the countries, and there's also the T2 round 2 countries that will also drop off. Counterbalancing that is FH2 launch, but that game has nothing on Fifa for pushing hardware.

I'm guessing PS4 about 180K and Xb one about 170K for China launch week, if Ioi's estimate is right. If it ends up at 80K then it could be very close.

Well, so far China launch week seems to have PS4 narrowly ahead. Will be interesting to see what adjustments do. TBH I think PS4 is a bit on the low side because Shadow of Mordor launched to very good numbers (better than Fifa) in the USA but PS4 is shown as having dropped 9%. I think it's more likely that it was flat or even slightly up.

Europe will have tumbled of course because SoM won;t be a patch on Fifa in those markets. But I still reckon it will have held better than is shown and I wouldn't be surprised to see PS4 adjusted closer to 200K. Xb one rose much higher on launching in several Tier 2 markets and the official Fifa bundle, meaning it would have naturally fallen a lot, but China, SoM and FH2 compensated. So Xb one looks like it's about right.