Hello,
Thank for your information about the issue.
Manual CAN1 can be used to read parameters from a single vehicle, since i suppose you will not be reading data from 2 seperate cars with one FM device Manual CAN2 option is not available in newer versions of configurator, CAN2 can be used for other purposes such as tachograph, CAN2 parameters are configured at seperate sections of configurator.
Best regards.