I don't think "little" is the right wordyou are getting a little too annoying..!!
6 controlled Kyuubi chakra + 6 Naruto Yin chakra = 12 chakra + 6 sage mode chakra = 18 chakra level.
I'm sorry but I think you just don't get it>·<The left most and the right most are not equal. Please avoid from mistakes when you are making chain equations and adding some stuffs. It is the worst use of equal symbol. I hate from those who make this mistake.