if you're using flac to fix sector boundary issues (and you do have sector boundary issues), it's best to flac an entire set at a time. This way, if you end up burning the show to dvd or playing the show via pc, the entire show would play seamlessly. If you fix sector boundarys on a disk-by-disk basis with a set spanning more than one disk, Flac frontend will pad the last track of each disk to fix the sector boundary issues. This could make the transition between the last track on the disk holding the first part of a set and the first track on the disk holding the second part of the set a bit choppy.