Right, so 7.7 million for the Wii, or 8.5 million for the X360. Both machines should sell around 2.5-2.7 million more for the rest of the year, give or take a bit. That leaves the Wii at 5.0 - 5.2 million and the X360 at 5.8 - 6.0 million.
If the X360 sells similarly to how it did in 2011, and this seems very likely, it'll reach that in September in mid september to early October. In other words, there's no holiday increase to worry about for the numbers here. Just Quarter 1, Quarter 2 and most to all of Quarter 3.
In order for the Wii to make 100 million by early September, it would need to be down only 10% YoY. That's obviously possible, but it's really very unlikely. Just look at the Wii's quarterly sales for 2011. Quarter 1 was 2.25 million, Quarter 2 1.95 million and quarter 3 was 1.6 million. It's in a heavily downwards spiral, and reaching the end of its life. Nintendo has shown with the 3DS that they don't want their old machine competing with the new one, so a price drop for the Wii is really rather unlikely. A 30-50% drop YoY is far more likely.
A 10% YoY drop, which would be needed to make 100 million before the X360 reaches 70 million is incredibly unlikely.
