Dear Audiofeil: Yes it is but any one can use it as main counterweight like in any static balance tonearm: you set to 0(cero ) the VTF dial and aply the VTF through the ( a,b,c ) sub-weight, that's all. IMHO works really fine, you can/could try it and " see " what happen by your self.
regards and enjoy the music.
Raul.