I have read through all your previous posts. I am assuming you are not a hair professional as you have no idea what to do with colour.
Koleston, along with all the other professional brands, may seem simple to you, but it is not as simple as looking at a shade chart and thinking "that looks pretty."
You said in a previous post that you want to brighten your medium/light brown hair, and to kill the red tones in it. Well, neither 4/0 or 4/07 will do either of those for you.
Go to a salon and get them to do it. If you are strapped for cash, go to a college and get them to do it.
It is actually breaking the rules of this site to give a non-pro advice on how to use professional products.
Good luck.