There are also reports that the state of charge of a LFP is harder to map than a NCM, and Tesla have less experience of this to date. So it may get better.
This tends to be the case. I have one old LFP pack that still gets some use, and guessing SoC from terminal voltage is near-impossible, especially over the range from around 30% to 80%, when there is almost no terminal voltage change that can be mapped directly to SoC - other factors, mainly temperature, tend to have a massively greater impact.
The SoC estimation system I've found tends to work most reliably is to just measure energy in to the pack during charge to 100%, measure energy out of the pack during discharge and try to apply compensation for the varying pack internal resistance minute by minute. This can be sort of done by measuring voltage droop under load - a cold pack has a higher internal resistance, so the terminal voltage tends to droop a bit more at any given load current. It's still a pretty imprecise art, though, as lots of short duration, high discharge current events can throw things out a fair bit, as can longish periods of relatively low discharge current.
I've no doubt that Tesla have put a lot more effort into trying to estimate SoC, but I doubt that they can do it to better than about 10%. Coupled with a pattern of use where the pack rarely gets charged to 100% (which would be typical for most cars), and the inevitable drift away from an accurate residual SoC that automatically leads to, and it seems probable that the SoC estimate may not even be as good as 10% some of the time.