Low volume levels from CDs that were burned on the VS-2400CDare usually due to lower mixdown levels when mixing down in the Mastering Room. In the VS-2400CD, look at the MST level while bouncing down and/or mastering in the Mastering Room and be sure that the meter is averaging as close to 0dB as possible--without going over and distorting.
If the meter is averaging at -12 or lower, rebounce and/or remaster the song(s) with the MST meter level higher. This can be accomplished by raising the individual track faders and/or raising the MASTER fader when bouncing and Mastering. This will allow the hottest volume levels possible to be burned to CDs.