Adam Yes, I had to increase disk space on my control server, since I had not planned for it to run through the control server. It is fine that it does, but it did catch me off-guard last week while I was importing Plesk sites.
It was actually through watching disk space live, that I was alerted. No doubt those who had done cPanel imports were already aware of this.
Ended, well, however. And thanks again Adam for finding that mail import bug on the Plesk side. You took care of that super fast, and I see the fix is in the 10.3.