I see ST offers a lot of style end caps ,I understand that in a 4'' application running open end cap #405-3046 = 10 discs, does this apply for all open type ST end caps or only the one metioned above, are the other styles like #402-1005 (grate open style end cap )just a decorative add on to be used with the closed endcap or does have the same 10 disk princeple as 405-3046, thank you...