I'm not saying I'd trust it. Just that it's not bare.
The lineman who came to do the transfer of my service entrance had been working on the I-35 bridge collapse the days prior and might have mis-spoke about the voltages here. I know the distribution voltage up North is somewhere around 6,5-7,2K as I asked about being metered at it.
So I could run lines at peak voltage to all corners of my property and then step down. They said no with some emphasis added.
You're correct that actual measured voltage vs rated voltage is higher. 240v will routinely indicate 330+ with a meter. I just go of common reference voltage because it's easier to follow. 208, 480, 600, etc are all utilized in 3ph industrial services here, so that confuses people when you start saying voltage read vs the voltage common use. I tend to only talk to people at this level when discussing industrial applications. My "shop oriented" buddies eyes glaze over when I start telling them to get 3ph motors and VFD's to save money. The little plastic box with a control panel might as well be voodoo from the expressions I get trying to explain how easy they are to use.
Every time I stop a VFD driven motor it lowers my power bill. For some unknown reason, the regenerative braking scrambles the brains of our digital service meter and it thinks we're pumping back more than we used. The more I work, the cheaper our bill gets.