Re: Layman question: Change DNS to 18.104.22.168, is the usage volume still ROGERS' ??
which dns server you use does not have any effect on your usage as measured by Rogers. dns is simply the mechanism used to resolve a fully qualified domain name (fqdn) such as www.rogers.com or www.google.com to an actual IP address which is then used by the network to perform the actual communication between your computer/iPhone/gamebox/whatever and the computer with which you are communicating.
dns is a small but essential part of IP communications, as was recently demonstrated by the Rogers outage, where, as I understand it, the Rogers dns servers were not functioning correctly.