I guess this means subtracting PS4's sold-through numbers from EA's estimates is not the way to go (in fact, it's a terrible way to pinpoint the XB1's WW sales) and confirms that both companies use different methodologies to arrive at their numbers.

I think the best way to narrow down the XB1's WW sales is to go with a US percentage range to come up with a ballpark estimate. We don't know if the US:WW ratio has largely remained static, shifted in favor to the US, or shifted in favor WW (though I think the third scenario is the least likely). Let's say the US makes up between 55% to 60%. Extrapolating from the approximately 20.12m US sales from NPD, the XB1's WW sales fall somewhere between 33.53m to 36.58m.

I don't know what kind of information Niko have access to, or if Zhuge based his comment on information he had access to, or something that was made public. That's why I asked.

Correct me if I'm wrong, but haven't people been able to discern that certain months were up or down YoY even though Microsoft didn't outright say so, by piecing together information we got from all three companies?
I haven't kept track of their PR as of late, so I thought they may have accidentally revealed something that people picked up on.

I don't know what kind of information Niko have access to, or if Zhuge based his comment on information he had access to, or something that was made public. That's why I asked.

Correct me if I'm wrong, but haven't people been able to discern that certain months were up or down YoY even though Microsoft didn't outright say so, by piecing together information we got from all three companies?
I haven't kept track of their PR as of late, so I thought they may have accidentally revealed something that people picked up on.

I'm not comparing Xbox to PS4. So I don't see why you continue to. 

I'm looking at Xbox, on its own, and comparing it to itself (2018 vs 2017). I don't see a way that it'll be up YoY. And the numbers could be down for several good reasons. No X launch this year, for starters.

1. Having the best looking multiplats (on console) isn't going to matter much (I'm not seeing the One X suddenly jumping ahead on Amazon, for example). So, again, that's moot. CoD and Fifa will continue to sell many, many more units on the PS4. This is critical, because for fortunes to change, people have to ignore the PS4 versions of those games. 

2. More games than last year should help, yes, but they'd also have to be system movers to really change the bottom line.

3. Early Access Program. For it to make a dent, we'll have to see the trend on Amazon (the only place we can have even a slight idea of Xbox One is doing).