That's what I believe as well. FLAC is still compressed at some point and you can also vary your compression which makes me question it's prowess as a format
I think the fewer conversions, the better. My CD to .wav rips have all been excellent. Converting my .flac to .wav has not always sounded as good. Although .flac is lossless, it is still compressed. Not being a software engineer, I can only guess that this might be a possibility for a difference in sound.