Hi @FrehelDenis,
If you use LB Deconstruct Matrix component, you will see that the component produces a header (brach1) direct (branch2) and diffuse(branch3) components for the Perez sky (145 sky patches). You will see that in both branches 2 and 3 there are 145 values. These are total direct and diffuse component totaled for the hours of the year you select on analysis period.
The image below shows the values for one day.
The image below shows the values for one month.
If you observe the 9th items on the second branch, you will the increase in value when we look at the whole month.
For your analysis, you will be able to do the analysis by changing the months on the analysis period component. It will be 12 simulations.