I doubt Mr. Hoffman would say the grooves are formed "during the "squashing" of the vinyl to the stamper.
No, RTI does not use a different process. My point is he gave an incorrect answer and folks will believe it.
To his credit he did point out "part 2" was simplified but I feel he added to the simplification of the processes with his answer.
FWIW, the metal part in the video is called a master. It it plated again to produce a mother and the mother is plated again to produce stampers. When more stampers are needed the mother is plated again. When the mother wears out they return to the master and make a new mother. And on and on....'til the master shows wear.
No biggie.