The top percentage of players are overwhelmingly better at the game than we are.
We regret not stating this more clearly in the previous explanation, but said premise is the reason why we do not release content tuned precisely as it was when the battle team’s balance testers cleared it.
We always add a little bit extra to the boss values before rechecking the fight and releasing it live.
The team responsible for balancing boss fights does so without debug commands and at the appropriate item level, employing available materia, foods, and medicines while experimenting with mitigating actions and various job compositions. Yet we recognize that player skill far exceeds our own. If we were to ship content with the same values which challenged our battle team, the top raiders would be deprived of that by-the-skin-of-your-teeth victory in the initial week of release.
Based on the team's skill and our experience, that "little bit extra" usually translates to:
Balance test clear values +1-2% HP