With some assistance of Guillaume Filion the fifth pool.ntp.org name server is now running the new DNS software, too. It's located in Germany. We have a few more servers offered by volunteers ready to be setup and we'll work on that over the next week or so and then we'll experiment with how best to use them to get the best possible performance for the pool users.
The difference is that now pool operators shouldn't see "spikes" in traffic, unless a big ISP caches the DNS entry and gives it out to many many many clients. If that happens we'll experiment with adjusting the TTL of the served records (The "TTL" is the time-to-live, the time the data should be cached by the end-user nameserver).