OK, I guess I got a bit confused by the name returned as the IP Owner on the whoismydns results, and the IP addresses not matching those I entered into the DNS settings. I ran the test on several computers on my network. Two of them have the OpenDNS servers entered directly in the network settings, while the third is using the router DNS settings. The whoismydns site reports different IP addresses for all three computers, but when I search the IP addresses, they are all reported as belonging to OpenDNS. I also ran the test on my phone again today and got similar results as I am getting on my home network, where before it was actually reporting the OpenDNS server IP address entered in the network settings.
Thank you, John, for your reply!