I bought a chipset kit directly from EKwb for the Z87 as påart of the kit for Maximus VI Formula. as can be seen on the left standoff it is not straight and not all the way down. the issue seems to be the threading  in the block itself which was not completed accurately as I tested with one of the other standoff distances to see if I could solve the issue. I could not thus it is now on the MB but with only 3 screws.