MDCS Object Data Size Limitations Question

Reading the help on the Parallel Toolbox, it says for 64bit systems a limit of 2GB for "single transfers of data between client and workers in any job using a job manager as a scheduler, or in any parfor-loop."

I take this to mean for a serial job, each worker can only accept 2GB, while in a parallel job the limit would be X number of workers * 2GB. Is this correct or am I way off? And on this topic is there a difference between passing a file vs passing a data variable already locally loaded?