We don't allow TTL modifications from users to keep the load on our DNS servers low. You can use alternative DNS servers if you feel our DNS service is insufficient for your needs. We believe we have competitive prices and features compared to the competition.
OK, then the question is, why do you not allow users to modify TTL, and why would someone prefer Dynadot over another registrar that does? Can we call you to have it modified?
We do not allow users to modify the TTL. Also, if you are using Dynadot DNS, the TTL is set at 4 hours or less. I don't know where you're getting 12 hours from.