Thanks, I think I'm starting to understand what happens there 
"GPU VID" is always the iGPU value. There are 2 problems however:
1. There seems to be a problem with reading of GPU VID straight from the CPU - sometimes it returns 0 V.
2. The position of this value is sometimes wrong because of other sensors appearing/disappearing.
The fact that with disabled nVidia GPU during HWiNFO start the GPU VID appears after some time (and as the last entry in the sensors list) is related to the 1st problem. But I might have a workaround for this (even though the hardware seems to return 0V sometimes).
When you see the "GPU VID" entry, do you see it fluctuating between 0 V and the correct value ?

"GPU VID" is always the iGPU value. There are 2 problems however:
1. There seems to be a problem with reading of GPU VID straight from the CPU - sometimes it returns 0 V.
2. The position of this value is sometimes wrong because of other sensors appearing/disappearing.
The fact that with disabled nVidia GPU during HWiNFO start the GPU VID appears after some time (and as the last entry in the sensors list) is related to the 1st problem. But I might have a workaround for this (even though the hardware seems to return 0V sometimes).
When you see the "GPU VID" entry, do you see it fluctuating between 0 V and the correct value ?