I guess those constant changes are due to the different CPU steppings and the advancements made in the manufacturing process.
I killed a Q3QR A0 hexa after ~10 minutes on SS (-30C), and I was only running Cinebench at ~1,65V Vcore. So it stands to reason that the same CPU would have died running WCG @ 1,55V Vcore on water.

As I said, I would not recommend going over 1,4/1,35V Vcore/VTT for long term crunching unless you are prepared to face the consequences.