The LED chart is not a chart, in the true sense of the word, but it looks nice and is a good choice to illustrate Variance analysis report. We make it so that, after analyzing the percentage for which the plan was exceeded or missed, with the help of the REPT function, generate a certain number of “squares” to illustrate the obtained result.
When you write DAX expressions it is a general recommendation not to overestimate their complexity. It is always better to create several measures and further consolidate them within the new formula. The code is more transparent, and there is a lot less chance to make an error. Since recently DAX also allows making variables. They are used to create measures that will be used to create an expression that returns final result.