honestly i'm not too sure how it works, cause i've used hecatonchires at 45% bonus (lvl 55), and phoenix at 40% bonus(lvl 85-100) and phoenix seems to actually give my partners a bigger boost in atk or something? maybe i'm high.. but yea, without limit breaks she's generally weaker than the others ofc, but still gives a bigger bonus.. though it sucks cause of the no hp bonus but... 25% burst can be nice. also her eido effect gives ATK++ which makes a noticeable difference, so she's really good for my fire team. also have sleipnir wo have another 50% bonus, better than my garuda/quetzel for sure, even though they're a little higher level. maybe in the future i can make them more limit breaks..