Does New Game+ have to be ran specifically on a 2nd play-through? Or can the player's file be one that has already beaten the game multiple times? I didn't see anything about it in the rules, but I would like to make sure so a file that has already beaten the game 5 times can't be considered as a cheated run.

I'd like to note that if the answer is the latter, then I can also create a guide for New Game+ in this game.

any game completed file that can access the grade shop is good for running NG+