TurboActivate doesn't care about the architecture of the OS (32-bit vs. 64-bit) or the edition of the OS (e.g. Premium vs. Home vs. Ultimate). It does look at the "major version" of the OS (e.g. XP vs. Vista vs. Window 7) and if this version is changed then it counts as a "soft" change.
You already know what a "soft" change means, but for everyone else reading this a "soft" change means that TurboActivate sees the system has changed but it still says your app is activated. When you call the "IsGenuine()" function it will tell you you need to reactivated. If 2+ "soft" changes happen then TurboActivate no longer says your app is activated.
Does this help clarify things?