With each new release, FoCal gets easier to use and adds new and improved features. Version 1.6 still has some bugs in it, and sometimes fails to finish the AF fine tuning process. It does no damage and changes nothing in your camera when it fails; you just have to start the software again and finish the AFMA process to get a correct AF fine tuning adjustment
I understand that version 1.7 will be coming out soon. It will provide a better user interface for Windows users.
Until version 2.0 comes out, Rick of Reikan Technology says you cannot compare results between camera bodies. The software currently provides relative Quality of Focus results that allow you to do the AF fine tuning and determine relative focus quality between focus sensors and between apertures for a given lens. You can see how your 51 focus sensors compare with each other.
The Mac version has not been released...the last time I checked.