I’m not sure how many people are aware of this, but Civil 3D 2010’s default out of the box distance reporting is flawed for some styles. But it is an easy hack. Let’s take a look at it.
If you draw a closed polyline and turn it into a parcel object or even using general labeling with the Bearing and Distance or Distance Only labeling options, it reports all of the sides of the polyline the same length no matter what the actual length is. This could be a big ‘gotcha’ if you’re not careful.
The problem is the type of label component used. If you drill down and edit the styles for the Bearing and Distance or Distance only, you will see that it uses the component of General Overall Length. The key word here is OVERALL. It is looking at the entire polyline length and reporting it for every side of the polyline.
By changing the label component to General Segment Length, it will fix this error.
The other labels that use the Distance component are correct out of the box as far as I can tell.