Say you have Static mesh A which is 1000 tris, and it’s a crate. In the Tris column, it will list the tri count for each individual mesh, so Static Mesh A will have 1000 as the value. (The value of one of them). Say you have 5 of those crates dispersed around your map though, under Sum Tris you will see 5000 tris as the value, which is representative of the total number of Static Mesh A within that scene. Hope that clears it up.