Amazon charts may be useful in looking at how software is selling but I seriously doubt that for titanfall when so many sales are going to be in the bundle anyway
That's the problem though the postiioning between the XB1 and the PS4 didn't change much on Amazon between Jan and Feb. even though XB1 was so very close to PS4 in overall numbers sold for Feb.
January bestsellers
PS4: 3 XB1: 16
February bestsellers
PS4: 3 XB1 [standalone]: 16 XB1 [TF Bundle]: 71
And yet overall XB1 increased its sales 84% from January to February and almost beat out PS4
Nothing on Amazon's best sellers really indicated that
Amazon will only become a good indicator of console sales if the same proportion of each console is sold through Amazon. Clearly that doesn't seem to be the case as quite a lot of PS4 sales seem to be through Amazon relative to XB1 as the lack of positioning change would indicate