The new comScore smartphone market share numbers are out and the weirdest number by far is the Windows Phone market share shift between October and January, when it actually shrank by 0.1 percentage points over three months to 3.1%. Of course, Nokia’s (NOK) Lumia 920 has been one of AT&T’s (T) top 3 models for the past two months. Verizon (VZ) has been selling the Lumia 822 as a free phone with a two-year contract. HTC’s (2498) new Windows model 8X has been at Verizon and AT&T since December. Nobody expected Microsoft’s share of the US smartphone to rocket with these new devices, but how can it be going down at the same time the BlackBerry (BBRY) market share is collapsing?

According to comScore, the BlackBerry market share between October and January tumbled a steep 1.9 percentage points, slumping to 5.9%. Windows and BlackBerry devices are often viewed as vying for the same sort of consumers, so a BlackBerry market share slide of this magnitude should have enabled the Windows camp to pick up at least half a point of share over a couple of months. After all, the new BlackBerry devices won’t start launching in the U.S. market until March. But it seems that Microsoft wasn’t able to exploit this period of extreme BlackBerry weakness, not even with several major product launches for both of the two biggest U.S. mobile carriers.

This may well tie into the horrendous February sales performance HTC just announced. It is possible that the new Windows models simply aren’t connecting with American consumers at all. It will be extremely interesting to see what happens when the Blackberry Z10 and the HTC One hit the American market over the next month.