If you have outliers in your data, then it is rally hard to use conditional formatting, sometimes positive values turn to negative color and sometimes the opposite, so it is hard to rely on colors.
Easy way to fix it, is to use Min, Center and Max values.
For example if I have data from -20% to +200%
Then I’d like to use min: -50%, center: 0 and max:+50%
It gives a lot better overview then and static results for every period.