It shouldn't take much more than that, it anywhere near it - IIRC there is a limit set, think it is 20, to the number of clients who can download their VC simultaneously.
And once the VC has been downloaded to the client successfully - it will be deleted from the EV server.
The other thing to note - after the first download, there should be minimal downloading of VC data if pre-emptive archiving is enabled under VC settings.
The cache is also used by PST Migration, and FSA Archiving when the target is a Celerra.