The effect of the fix APMDATA-1656/APMDATA-1964 is actually dependent on what sort of appliance it is using. When applying it on a _physical_ APM appliance with enough memory, it will set fglam heap size to 6GB.
In your situation you are using a 12GB Foglight on a _virtual_ APM appliance, the memory allocation will be as below:
appliancemon ALL 256 MB
foglight ALL 11.2 GB
7.3 GB for JVM (6 GB heap)
1.7 GB for MySQL (1.2 GB innodb)
2.2 GB for FglAM (1.5 GB heap)