A lot of spray can be saved by installing foliage sensors on your airblast sprayer. Particularly when there are gaps in the orchard from missing trees.
High density operations don’t often get the same benefit because spaces are small and the trees are generally the same hight, forming a solid wall.
Further, the ‘eyes’ are sometimes fooled by trellis wires.
This video shows Gillison’s Sonic Spray on a Turbomist spraying water in Apple Orchard (2013).