Some information on how the FMS works can be gleaned from the FMS lite package that was released for the 2009 game. Here's the user's manual:
http://usfirst.org/uploadedFiles/Com...Guide_RevC.pdf
I would add that I find it extremely frustrating that not only are we not allowed to look at the source code for the FMS or DS, we're expected to deal with their imperfections without even a general idea of how the field works (or doesn't).