If I'm not mistaken, Netflix uses multiple types of DRM (for iOS, PCs, Wii, PS3, etc). The Windows DRM is for PCs and the XBOX, possible some others (Roku might use it, I think the NXP-chip uses Microsoft DRM).
This is actually the problem with Netflix on Android - Android doesn't have any DRM standard, so it's up to the hardware manufacturer to include it.
