My vote is to call it PA 2012 or 2013 (year), then the build number like you have eg 12.12.
By the way, some new 2013 cars are out already eg the Maxda CX5
For atleast a month already...
By the version date, eg 12.07 (eg July) vs 12.09 (eg September) it is hard to tell if there is a major change, eg from PA 2011 to 2012 with, thus the PA 2012 is still necessary. Hopefully you get the idea, to still keep the PA 2012 versions.
Keep up the great work Conexware team!