NTSB member Sumwalt addresses the recovery of non-volatile memory
In that video, he says PAPI angle was tested and found to be within 1/100 of a degree accurate. Not sure how meaningful that is. Think it would change more than that with wind and temperature (materials expanding and contracting). A PAPI vendor only specs it to within +/- 3 minutes of arc (1/20 of a degree).
Practically, this is no big deal regarding PAPI but it makes me wonder how reasonable NTSB is with other units of measure. Just because your calculator can read 9 digits . . .