That's for people who cheated their way up.
When you don't play the original level-up event in which you meet Suzie, her relationship is not set properly.
But what do you mean with reset back to level 6?
I just tested it again - I keep my progress in level 7 after using the cheat.
I think JD is reusing some images, but I'm not too sure about it.
You could ask him in Discord what his process is exactly.
Unfortunately, I have no clue at all how HS works and what "masks" are, or how they prevent from bloating. xD
My pleasure