I think it's designed this way: in order to have unity gain, you are supposed to raise the direct volume signal. It's not designed to be used 100% wet as some other fuzz pedals that also have a clean blend capability (wren and cuff pickle pie comes to mind). I run mine with clean at 11 o'clock, wet, tone and fuzz at noon and I don't have a volume issue. Also the tone control position will have an effect on the perceived volume.
But I think that if you want to use this pedal 100% wet, you might look for a different pedal, as you will have volume issues.
But I think that if you want to use this pedal 100% wet, you might look for a different pedal, as you will have volume issues.