This is a concept i have been struggling with. I don't think it's the grind of the flour that makes a big difference in the browning. When I first started making pizzas in the Blackstone oven at really super high temps, I wasn't getting the browning I liked either. I was getting it in the Kamado but not on the Blackstone. I think I have sorted out the 'why' on this after completely reading the Ken Forkish book...
It's the combination of hydration and temperature that allows the browning to happen. My problem with the the browning at 900+ degrees was that my dough hydration was too high. I was using 70% hydration. That much water in the dough at that high of a temp was keeping it from browning the way I like. That exact same dough (basically) with the same flour and other ratios browned nicely with the leopard spotting at 900 degrees with a 58-60% hydration dough. That same 70% hydration pizza dough cooked at 550 degrees browns nicely because the extended time allows enough of the water vapor to dissipate that the browning can occur.
That browning is a maillard reaction just like the browning of a steak crust.
@Mewantkj - do you agree with this?