Like Japan matters for a western game
GTA V sold more than MK8 in Japan first week, and is over 800k now. (per Media Create numbers at least, Famitsu has MK8 about 23k ahead). Watch Dogs won't sell anywhere near that well, but clearly a western game can do well in Japan.
It also doesn't change my point about the number of days the games had or the irrelevance of average sales per platform.