So totally disagree with this statement.....
Ok....forgive me but lets walk you
through it.
You have a 10 ml of mixed ready to go IC. You want to make 30ml of a recipe and use that 10ml so in order to finish filling that 30ml bottle you would say
30ml bottle minus the 10ml(already in there) =20 ml.
To keep the IC @ 1% in a 30 ml bottle, only add IC to finish mixing to 30ml, so you want to add .02ml of IC along with the rest of your recipe ingredients to your new recipe.
I know clear as mud, right?