The z mounts are .1mm looser because of the orientation they print and the fact that they are clamps. But it works out as a wash when printed usually. Small imperfections on the print surface of the tube section of the tool mount can cause big issues. is there any blog or anything, slow accelerations causing rounded corners? Either way wrap some sand paper around the tubes and give the tool mount a quick scrub, that should clear up any slight imperfections.