No, sorry this is just a coincidence that the transpose slider moves by 11-12 semitones on Windows.
On OS X it does not work like that, where the mouse wheel has acceleration.
The way it works: the operating system provides the amount of movement. The slider uses that value, so this has nothing to do with semitones, this is all by chance.
BUT: this could be a good improvement, so I noted this as a feature request.
