Defend Berk dragon stats are inaccurate

Reading individual dragon stats to figure out which dragons to train I realized that even though Toothless has lower firepower and health he is MUCH stronger than other dragons at the same level (according to the little symbol on the Defend Berk menu) that have MUCH higher Defend stats… I have a hard time wrapping my brain around the mathematics but I don’t think any of them are accurate… I have noticed that a few dragons that are leveled up HIGHER than toothless and that possess really high stats don’t come close to Toothless’s power or defenses… what’s up with that??