I read a post on a message board that said:

"While most people know the ins and outs of Tetris like clearing 4 lines is making Tetris and being able to rotate the Tetriminos either left or right with the respective buttons, The Grand Master introduced three new systems to both improve the gameplay and rate the player's skills. The most important feature is the Grade Recognition System, created by Bullet-Proof Software (Yoshi's Cookie) is another novelty for this game. What it does is to rank your performance based on how fast and precise your gameplay is, technique basically means more than "How many Tetris you've made through your gameplay" along with score requirements like almost 160,000-180,000 points to reach the Grand Master level. Those 19 levels mentioned are 9, 8, 7, 6, 5, 4, 3, 2, 1, S1~S9 and finally Grand Master, also, the required score for the Grand Master rank also varies according to your skills."

Is this true? Does Yoshi's Cookie have a grading system like TGM? Or is he saying that Bullet-Proof software invented this grading system in some other context?