I'm building a 3 line stack; 2 centerlines outside, 1 solid line in the middle. They are all parallel. 1 length is fixed. That's not important, I'm just listing what I can think of that I have ruled out is causing the issue. It's a visual issue. I dimension the distance from 1 centerline to the solid line in the center to a value of ((1/8)*25.4)/2 or 1.5875 and then I dimension the distance between the 2 centerlines (they are on either side of the solid line, parallel remember) to ((1/8)*25.4), 3.175 or double that first length; so the two centerlines are double the distance apart as the distance from 1 centerline to the solid line in the middle. But visually it doesn't match. The distance is off balance to one side or the other. 

Now the error has changed that the two centerlines are 3.175 and the solid line is 3.175 away from either centerline and it is visually a balance 3 line stack with the centerlines equally distanced from the solid line. The dimension tag references off the lines (it draws a tag into thin air).

As I was working it happened before and it eventually rendered correctly and visually was correct as well as mathematically correct.  I'm doing my best not to overload the program but the insistent errors in calculating a dimensioned drawing of just simple flat line geometry is too much for the program. I'm a little disappointed that I am able to catch the abundant bugs with this software.

Just venting I guess.

Edit: I just toggled one of the centerlines to a solid line and it fixed itself. I guess it's something to do with designating a line a centerline. I'm not sure I understand all the unwritten rules of the interchangeable distinctions.