That doesn't seem anywhere near right. 250VACrms is the nominal voltage, and 125VACrms the nominal split voltage. I've seen our actual VACrms closer to 254 on many sunny days for several hours, and I've even seen it around 256. Half of that would be 128VACrms. Your chart says anything above 120VAC (240VAC unsplit) is a no no for more than 3ms!! For the system to trip for a relatively normal voltage that is under the nominal voltage for the reason of being "too high" would be a really odd reaction. The original electric system design was 250VAC, but for some reason, they just kept lowering the name of it to 245VAC then to 240VAC due to typical line losses, so they settled on the standard of calling it roughly 240VAC for easier rough calculations. I heard in some cities they started even calling it 235VAC, but that's just being cheap. Your chart says 120VAC (half of 240) would be considered "prohibited", an absurdly insane remark, despite the name commonly used in most discussions and documents now saying 240VAC.
The voltage goes down at night here. Right now, I'm showing 122.7 on one leg, which would be 245.4VAC, at 23:26. I live in a suburban rural area, so plenty of lines to lower the voltage.
I wonder if because I live in a big State, that they want to keep the voltage higher than high density urban areas, so they get more value out of their wire thickness, whereas in scammy Eastern cities where they have tightly packed urban areas, they may want to prefer to spin the meter faster to bill more kWh per tariff rate. Either way, here, it's measured by kWh, since the new "smart" meters know both voltage and amps, so that scam doesn't work any more.