Luke 3 boost and P/U comp setting

I recently bought a Luke 3 guitar (used) and I’m missing the manual to the electronics setup. I know how to setup the boost, but I’m puzzled about the other pot? I don’t know what it’s purpose is. something with “position 2 and 4”. I really have no idea what it does. Can you give some info or a manual of some sort?

Support sent me some information but still I have no idea what it does.

Setting the dB level of the single coils to the humbucker? In what way? Does this setting affect the levels only when the boost is engaged?

thanks a bunch