dns servers differ

I have noticed that the DNS resolution implemented by C.I.S 6.1 is different of them posted in the website. Why is that and which is the correct? The one from the website or of C.I.S 6.1?

The website lists both the primary and secondary DNS server addresses from the new SecureDNS service.

When CIS sets up the server addresses, it uses the address of the older service for the secondary address. This way, if the newer service goes down for any reason, the older service is there as a backup.