Again, I'm not saying that's *acceptable*. I don't know why everyone seems to think I'm some kind of advocate for the power companies or something.
All I'm saying is the 600% number is just pure clickbait intended to induce outrage. Yes, these meters need fixing, but there is no indication that this is some kind of conspiracy theory to overcharge customers. Measuring power usage accurately is actually a difficult engineering problem when terribly non-ideal loads are present, and the 600% figure came up during a practically worst-case scenario test, with meters using a particular technology susceptible to it (note that another tecnology under-measured under the same conditions, so it goes both ways). The problem is simply that meter testing standards do not test for this, so meters are not certified to be able to deal with it.
What's the actual effect with real-world loads? We don't know. Someone needs to run a better study to find out. The testing standards need to be updated to test a wider variety of load conditions.
The simple fact of the matter is that no meter is ever going to be perfect, and in fact, some load conditions will never work due to sheer physics. Industrial customers are actually charged higher rates if their power factor is poor, because in fact using misbehaving loads like these puts a higher strain on the grid and increases transmission losses; residential users are actually getting a good deal there because they can have whatever horrible power factor they want and the power company has to suck it up and deliver it. Would you expect your meter to accurately be able to measure the power consumption of a load that averages 100W, but actually draws 10000W during 1% of the AC cycle? Would you consider that a reasonable load? It's great to think AC power is a magical perfect sine wave and you're allowed to draw whatever current waveform you want, but the laws of physics mean that isn't the case. The more you deviate from an ideal resistive load, the more problems you're going to cause. These meters should be improved to better deal with less than ideal loads, but no meter will ever be able to deal with an arbitrary load. Because physics.