There should be an option to show the duct and pipe drop/rise symbols ONLY for ducts and pipes that are being cut. Same goes for their line weights. As the architect, it's helpful to see and understand which risers are which via the symbols, but I definitely don't want to see the drop/rise symbols at every change in elevation. The ductwork is often just faded into the background of RCP's, but in doing so, it lacks the graphic cue that one of those rectangles is a riser that's going floor to ceiling.