I appears that the generated numbering system is wrong when a minor key is assigned to a song. I checked a bunch of songs rooted in natural minor & the chord numbering (e.g., sharps, flats, etc.) appear to be drawn from the parallel major key (NOT the relative major key)

I may be confused, but songs in A minor with only diatonic chords should have no sharps or flats; however, the number system seems to assign flats to chords as if the song is written in the parallel A major key. I checked a bunch of songs & drafted my own to check this. It seems to be corrected if a song is assigned the relative major key....then the autogenerated #s follow a Nashville numbering system.

Please let me know if I'm trippin', but I don't think so (kind of a theory amateur, but not total newbie).