Board Thread:General Discussion/@comment-24031741-20140104200613/@comment-5398287-20140104203649

The answer is in your description - "presumably". When Shunko was described, mastery of Kido was never mentioned, no was mastery of Hakuda - just that the technique combined the two. The fact that they are both Hakuda masters stems from them being the leaders of the Onmitsukido and thus training to attain that level. Thus far, Suì-Fēng has only displayed an expert level of skill in Kido, and since perfecting Shunko indicates nothing about that increasing, it will remain as such until someone says "[Suì-Fēng] perfected [her] Shunko by increasing her skill in Kido" or Suì-Fēng displays a higher aptitude in Kido. The same applies to Yoruichi.