This is what, MBR? White Len has never been that cheap in AC. Kouma's 6C j.C should do way more than what, 600 damage? Also, White Len had the infinite meter, not Kouma, and as far as I could tell, Kouma had no meter at all.
I know MBR had a White Len Boss that was like that, or at least I'm pretty sure. Even still, you aren't hitting any combos, which is a bad thing.