I am an astrodynamics engineer working on validating my own drag model results against Orekit. In my investigation, I have noticed the CSSI space weather data that are being used by the Orekit NRLMSISE-00 model implementation are the f107Adj and ctr81Adj values in the functions getDailyFluxOnDay and getAverageFlux. However, the NRLMSISE-00 model states:
f107 and f107A values used to generate the model correspond
to the 10.7 cm radio flux at the actual distance of the Earth
from the Sun rather than the radio flux at 1 AU.
which is a block of text that you can find at line 1804 of models/earth/atmosphere/NRLMSISE00.java. This appears to indicate that the Observed values, rather than the Adjusted values, should be used.
I was not able to locate a conversion function to readjust these values to their correct flux. The choice in setting these values causes significant deviations in my implementation, especially during periods of high solar activity. I wanted to bring this to your attention and either receive clarification on the choice to use these values, or perhaps be pointed to where a function call is converting them to the actual distance requested by the model.