You seem to be suggesting it.
DFF3D is more downward wide beam device and not really a true side-scan as it is just using the outer side beams of the down transducer for a side-scan "like" screen.
True side-scan would start at the water surface like our 235 or 455 side-scan options. Because they have a beam out port and beam out starboard it would have to be two cross sections, not just one. In what way would you use this feature?