I seem to have found a conflict with HWInfo, might be worth mentioning to save others hassle troubleshooting.

It seems if HWinfo has been opened in sensors mode it prevents AMDMemTweak from applying any timing changes until the system is rebooted.  
Even after quitting HWinfo any changes in the timing sections still will not apply, they just revert back to the previous value when I press Apply.
Changes to the Clock/Voltage/Fan Control sections still work, just not the timings or REF adjustments.

Any chance of adding a GPU Memory Errors counter to the tool somewhere so I can ditch HWinfo?
Or do you know of a tool that will show memory errors and does not conflict?