Dimension strings not adding up to the total length dimension string (2017)

[jledgewood]

i have a string of dimensions that do not add up to the total length dimension string. there is a dimension in the multi-string that is 1/256" off. i have my rounding set to the 1/256" so this way i get a true dimension. i would like to know if there is a fix for this? not necessarily a work-around. i am attaching a revit file that shows this issue.

[david_peterson]

I've seen this before.
2 things can cause it.
If you have a Cad file with large drawing limits (larger than 20miles) or an origin a large distance from the line work, that'll cause things to go wonky.
The other thing I've seen happen is somewhere one of those lines might be not perfect. Say it's 1/1024" off from where it's supposed to be.
Another check for that would be take a detached model and change your drawing units to millimeters and carry it out as many decimal places you can.
I'm guessing you might find one that's not right. Which throw the whole thing off as revit tried to add them.
Just a thought.