Hm, I wonder how they count the triangles rendered, since they could as well count the triangles which are rendered in shadow map passes...
I think this is the reason for this polycount. I saw this in several engines that their statistic tools displayed me way more tris than I put into the level. Probably these came from the shadow generation process, maybe also from creating depth maps, I am just guessing. But a fact is, that they generate additional tris and not just a few.
