Default [Q] Returning to HTC. Cant uninstall SU after following stpXstp

I cracked my screen.... luckily as HTC is awesome they have the HTC advantage plan that we are all a member of by owning a HTC One... I returned my phone to stock following the step by step guide here which all worked perfect except when I go into SuperSU now and settings>full unroot, it deletes the app, then reboots itself and when back online, SuperSU is back.... am I missing a step or did I mess something up along the way? Can anyone help pls? THank you

Guide I followed: http://http://forum.xda-developers.c...2&postcount=18