The Add-ons do work with Studio One 3 Fat Channel without the need for the Series III Console, however if it's embedded functionality that you're looking for without the need to run a DAW for realtime processing, that is reserved for the Series III Mixers only. If you need a solution for live sound in a rack mount solution, then consider moving into one of the Series III Rack Mount consoles instead of using a Studio 192 or Studio 1824 as those are designed for Studio use.