[Five]

in that case what you need to do is check the fingerprints against your recompressed FLAC files, if the old ffp verifies okay with the newly compressed FLAC files then there is no change whatsoever to the audio content. However, any tags or non-audio data will be lost in the process. But if the audio is identical & verified using fingerprints then there is no generational loss whatsoever from FLAC>WAV>FLAC and would be allowed.