I wouldn't trust the 1% for Rush (S) lv 20. It conflicts with what testers are saying on the comments page. The issue is that there are still a lot of questions surrounding it. Interactions with other +combo effects/stacking with multiple Rush skills are still mysteries.

Don't forget that for Tower Quest, kamihime can only be used once every fourth day or so. It's not just a quality issue, it's also a depth issue.