Likely it is less noisy...right?
Back to the drain issue, remember that these drain lines must not be extended, nor should they be brought in at the base of the cabinet. This makes it difficult for the unit to discharge water efficiently. Be sure the drain hose is above the level of the disposer or wherever it drains out, or water can siphon back from the drain and collect in the unit.
During the Normal wash, does it go into a drain cycle before it enters the rinse? If so, is it a forceful discharge into the sink?