May I ask what you mean by "back case reverse up n down" ?
Can you post a picture of your PAM288 caseback? It will help let us know what you are referring to.
Best,
Anthony
...corresponding to the dial? It's a screw-down caseback and you can not influence which position it is fully screwed. I suppose this could be an answer to your question.
BTW, hello to all of you, this is my first post here, though I regularly visit the site for years. It's simply great!
Best,
Bojan

You can see the text is not in a perfect horizontal position. But the back is in the perfect position for sure
Best,
Bojan