SolidWorks has been steadily adding options to Mirror Components for the last few releases. One of the missing details was the ability to control the point about which components were mirrored. In previous releases components were always mirrored about their centre of mass. For symmetric components this worked out well, however not all components are symmetric. The part I have created exaggerates the effect of using this option.
When mirroring without reorientation these options have no effect. But as soon as the components are reoriented the effect can be clearly seen. Center of mass is the option previous releases of SolidWorks used. Now in 2014 we can mirror the asymmetric components using the bounding box. This means that the outside shape of the part controls the output position rather than the center of mass.