I didn’t think Sam meant that Reb Chaim Kenievsky answered word for word what Reb Shachter said.
I remember that when, oddly enough, they asked Reb Chaim Kanievsky what the source is for Avram Fried’s song, he said it is nowhere in Chazal but perhaps somewhere else. Eventually, someone had the brainstorm to ask Avram Fried himself. He pointed to a Chasam Sofer that it was based on.