The manual says that the upper rail offset can be adjusted to +/- 5, 10, 0r 15 degrees. I'm trying to figure out how to set the offset to -5 degrees. However when I look at the assembly, the angle between the pairs holes marked 5, 10 and 15 don't look like they are 5, 10, and 15 degrees apart and when using the holes marked "0" the scale is reading 45.
I feel like I'm missing some necessary information here.