Nope what he would have you do is send the signal from the amp to the subs and then the speaker outs of the subs that would take low bass away from the main speakers and that is terrible for music listening. You want full range sound to the speakers so they have the opportunity to go as low as they can and let the subs fill in the bottom from there.
Everybody these days has HT (home theater) HT brain,

The way "the guy" wants you to set it up you would not be hearing the amp purely but through the subwoofer crossover. NOT recommended.
Do scenario A