My bad, my bad. Today is our fiscal year end and my brain is imploding.
SB only supports ff/rw with native file formats (mp3, wav, flac), not with any transcoding. Since SB doesn't have native support for Aplle Lossless and several others, transcoding is necessary, and therefore mucks up the ability to ff/rw within a song. Not missing much, though, when it does work it's archaic.