Break point damage is relative to a specific defender and their defense stat. In other words, Break point damage changes for each pokemon dragonite is up against. i.e. dragonite may need to be one level to get that break point against zapdos and a different one to get the break point against blastoise
Below is a link to a Trainer Tips video with links that will help you calculate what level you need it to be to get that extra damage against specific defenders and raid bosses!
https://www.youtube.com/watch?v=0qQpGUieWO8