It's quite simple. I use NortonDNS to block malicious sites ONLY. This is the SOLE reason I use NortonDNS and I can't believe you're changing it.
It appears that the 3 different presets use different IPs, but the basic preset (A) is blocking proxies, but is also a different IP from the old NortonDNS IP.
Why is the old IP gone? Am I just supposed to memorize it every time I want to implement NortonDNS? Is it going to be randomly phased out one day, forcing me to use the A preset IPs?
I have no issues with different presets blocking different things, but you MUST bring back the standard malicious sites preset.