I'll just put my 2 cents in :
The Wings statement doesn't mean Zoro=Sanji in strength/power.
Why? I'll make this super short:
1. Wings are the most helpful/contributed the most to Luffy becoming PK (hence why the full title is Wings of PK).
2. Zoro's entire contributions (what he did for the whole series) is 99% combat & 1% advisor/vice captain thing.
3. Sanji's entire contributions are very wide:
- During action, he does combat
- During action when he doesn't do combat, he does spy/tactical thing (eg Gate of Justice, Arc Maxim) or hero thing (saving nakama/people)
- During non action, he does his main job cooking, daily
- During non action, he does other things too beside his main job like advising Luffy (eg Usopp scene) or babysitting (eg Brooke's recruitment scene)
Since Wings are equal, which means both are scored 100, and due to the points above:
- Zoro's score= combat is 99, other thing 1
- Sanji's score= other thing is definitely more than 1 (because he does many things much more than Zoro), and his combat is definitely below 99
So, in/for combat, Zoro>Sanji, even if it's 99>98, and definitely isn't 100=100.