the order of the filtered mesh faces is srambled

I have a mesh object with irradiance value (kWh/m2) visualized for each of its faces. The irradiance value for each face is also stored in a data component. The total solar radiation (kWh) on the building surface is calculated as the sum of "irradiance X face area" for all the faces, and it was obtained from the Ladybug Radiation Analysis component.

I want to filter out those faces with their irradiance value larger than 1000 kwh/m2, and calculate the total solar radiation for those faces only. Something like what is shown below:

But before I do that, for the workflow shown below I set the filtering threshold value to zero, which means that all the faces will be selected.

However, the total solar radiation value calculated is not the same as the one calculated by the Solar Analysis component. and the order of the faces of the mesh seems to have been scrambled after I convert each face into brep to calculate its area.

May I ask how to get the area of each face with this mesh and in the same order as that of the irradiance values of these faces?

Thank you!