Allright!
I think I have fixed it. Least it appears to be working in user define fan curve section. I have there now Ex Fan option and auto calibration seemed to work.
What I did is this. I uninstalled all Asus software with Revo Uninstaller Pro and used advanced cleanup option, then made sure there was no Asus folder left in %AppData%, also manually deleting any leftovers in ProgramFiles etc. Then rebooted and installed GPU Tweak 2132 but no joy. So I then turned off the computer and flicked off the power switch on the power supply, waiting until the power-LEDs on the graphics card went off, turned the system back on and I quickly noticed that the Aura for Graphics Card app icon under Tools in GPU Tweak was no longer greyed out (I had also problems with Aura Sync) so I reinstalled Aura Sync and that worked again after the reboot along with external fancontrol in GPU Tweak. Or so it appears.
EDIT: I doublechecked and I still don't see the Ex Fan slider in the list under the sphere button menu... and the control is not fully working either... It starts spinning for a second and then cuts out for a little bit...