To give you an example I uploaded the worksheet I use. I rather wrote another sheet, but that's kinda hard for me to still emphasize the problem I now encounter.
I only showed the commands which matter to the problem, the rest I ended with ':'. I also added text in red where I explained my problem.
To explain shortly:
The first procedure (is the first plot) depends on a '5%-rule', I can plot that one. No problem.
The second procedure (is the second plot) depends also on the (same) '5%-rule', I can also plot this one. No problem.
The third plot calculates a line containing the first procedure.
The third procedure (is the fourth plot) are two lines, which I want to convert with the fourth procedure, and inside this fourth procedure I refer to the second procedure. And this is where I mess up.
Hope it's better explained now. Thank you.