Since HWiNFO v6.14 (I believe) if you change CPU or iGPU voltage offset using XTU or Throttlestop when HWiNFO is already running then it won't show the updated settings. This used to work prior to v6.14.
This was an intentional change. It's quite unlikely for these parameters to change during runtime and constant polling of these values was putting unnecessary load on systems of many users where these parameters remain static all the time. Hence it has been decided to optimize the polling as much as possible in favor of the very small need for periodic polling of these items.
I have HWiNFO v6.28-4200 and I am observing that even if I reboot my system or come out of hibernation, I am not seeing this values get updated unless I Quit HWiNFO and relaunch it.
My machine has voltage offset of -0.125v from the manufacturer and sometimes it resets to 0 on system boot so I use HWiNFO to check the status and that's when I observe this behavior from HWiNFO. Right now I have to confirm these values using "CPUID HWMonitor" .