Dimension mirrored from reality

I have been working on a part for a few days now and havecome across a strange thing. Several features in the model aredefined using a sketch on one of the standard (front, side, top)planes which is then extrude cut from an offset to that plane to anoffset to that plane. In other words, a sketch on the front planeis being offset a distance away from the front plane, then extrudedtowards the front plane by a distance that is determined by alesser offset from that plane. The pros and cons of this method canbe debated seperately but the result of this is a correctly modeledfeature with a dimension that is mirrored. I have attached an imagebelow to better show what I am talking about. Is this a bug or isit a direct result of the method I am using?

The first picture shows the settings and sketch I used to set upthe feature, the second shows the resulting mirrored dimension(0.519 dim)

SolidworksSketching