[LAU] Ardour 4 audio export FLAC questions

Hello list, My googling did not provide me with sufficient answers, so I'm directing my questions here ;-) I made a 1 hour long project in Ardour that exports as a 635 MB wav-file. From Ardour the same project exports as a 566 MB FLAC file. However, if instead I use SoundConverter to convert the WAV to FLAC, the resulting file is 269 MB. Since both are FLAC I'd expect them to yield the same playback (though after finding a report at hificritic [1], I wonder...) Is there a way to check if those FLAC files are indeed 'audio identical'? And, obviously - if the audio quality is indeed the same - I much prefer the smaller file. How can I tell Ardour to compress better? Thankful for any and all input, Al F 1. http://www.hificritic.com/flac-wav-sound-quality-research.html