WHMCS = Billing system cPanel/WHM = Server Control Panel WHMCS can provision as many shared accounts across as many cPanel/WHM servers you need. In the latest versions you have server groups where it will evenly distribute account
provisioning when a new client signs up. So in short, you can have one system/account/server/vps with WHMCS. Which can technically provision on 1, 2, 3, 500, ...