Nope, I never power off my PSU and it happens to me. For some people Wattman doesn't seem compatible with Windows Fastboot.
Guys it doesn't matter if you never power off the PSU, Windows fast boot is invoked every single time Windows boots, cold or warm. Even with fast boot on, in some rare cases during a cold boot Wattman will load your previous settings fine. The problem is that with fast boot enabled, more often than not it causes Wattman to reset to defaults. It matters not if you power the PSU off or leave it on standby 24/7, that's a red herring.