Are you talking about Laptop?
Regular Hibernation saves the Memory as a file on the Hard Drive, and switches off the computer, and thus as nothing to do with Standby, or WOL.
Some Laptops have a propriety system that is a combo of Hibernation/Standby, and the computer is Not really Off.
Might be that your computer does the same.
Try WOL straight. I.e. No Standby, No Hibernation, No gimmicks, just ask Windows to shut down the computer, and check that it is really Off.
When the computer is really Off but connected to the external power, the ATX PSU keeps live voltage line for the WOL, and few other boot functions.
WOL is a Hardware function involving the PSU, Motherboard, and Network Card, and has nothing to do with Windows, or any other OS.