I was looking heavily into this a few weeks ago -- I read somewhere in the docs that you can only set a minimum grade for gradebook "manual grade items", not Moodle activities. However, I haven't been able to even set a minimum grade for a manual grade item. So it annoys me because the "0 - 35" range in the grader report just wastes space. I wish it would just show the Max value, like it does in the Gradebook Setup view.
Agreed and I noticed the same thing.
I'm also annoyed by options that are shown but can never be edited. My opinion is then just to leave them out.
And how about the data in the database? Every grade-item and every given grade has a grademin value.