Why grey and not white
The instinct in a food environment is to go white, on the theory that clean should look clean. In practice a white floor in a working kitchen shows every grease mark and every scuff from a cart, and the floor spends most of the day looking dirty even when it is not. Grey sits in the middle: light enough to satisfy an inspector that the floor is maintainable and readable, dark enough that the film of grease that inevitably exists between end-of-shift cleans does not read as neglect. Every commercial kitchen we have installed in has ended up here.
What a double broadcast actually is
Coloured quartz is ceramic-coated silica sand, and it goes down in two passes: a body coat broadcast to rejection, cured and scraped, then a second broadcast over it, then a flood coat and a topcoat. That produces a floor an eighth to a quarter inch thick that is essentially a resin-bound aggregate slab rather than a paint film, which is why it takes cart wheels, dropped pans and hot wash-down for fifteen years and why it costs $11 to $16 per square foot rather than $8.
The parts that pass inspection
What health inspectors actually look at is the perimeter and the drains, not the middle of the floor. A quartz system is turned up the wall in an integral cove so there is no floor-to-wall joint, and it is carried into the drain body and terminated inside it rather than stopping at the edge. Falls get re-cut where the slab has settled flat. Those three details are where cheap quotes save money, and they are the three things that will be raised in an inspection.