The droplet spectrum of the Lechler FD fertilizer nozzle is extreme coarse and comparable to the drop size of stream nozzles.
The main advantage of FD is to release the droplets almost horizontal at a low pressure, so they fall into the canopy just like rain by gravity. This is an important advantage when applying liquid fertilizer. Often times scorch is caused by mechanical damage of the waxy layer due to high kinetic energy and impact in the droplet or stream. This even more if application takes place after a rainy period or when there is a lot of dew in the canopy, which weakens the waxy layer.
For late fertilizer applications when the crop is already big (e.g. late application in cereals), it is recommendable to use a hose drop system like 5S and 5SL or the DroplegUL. With those systems, damage can be avoided because the fertilizer is applied into the canopy and not on the top of the crops.
Information links: FD nozzle , nozzle recommendations