(Edited) Using Amazon isn't entirely accurate to judge NPD sales. Here's why...

[SWORDF1SH]

Angelv577 said:
It's a good source to use for console predictions since it has been correct for almost every month.

Agreed. But if you see PS4 at 8th for the month and X1 at 9-15th(ish), I wouldn't be surprised if the X1 won for reasons explained in OP.