Oh, okay, thank you. I just took it for granted that with a number that precise, that accuracy was also implied from an NTSB communication or something that I'd missed.
That kind of accuracy can't be done from FR24 etc., for the reasons you've stated so we'll see what the Interim Report says.
Don't confuse precision with accuracy.
FWIW, that's almost certainly ADS-B-derived data, it's too granular to have come from ASDI.