Most beehives I have seen around this area, Northern Rivers NSW to QLD have 1 brood box. But some beekeepers like 2 brood boxes.
You could do an experiment and have 1 beehive with 1 brood box, and the 2nd with 2 brood boxes.
But then again even if you had the same setup with 2 beehives, the colonies could be different, with different results.
Here are some of the reasoningss I have heard (I think from memory) :
1 brood box is easier for inspections. Easier to find the queen. Easier lifting. Splitting a brood box when it gets full may prevent swarming.
2 brood boxes make a potentially stronger colony for when there is a honey flow. Extra honey for when there is a dearth (lack of food).