480 / 32 = 15
472 / 32 = 14.75
448 / 32 = 14
So 480 is allowed, and 448 is allowed, but 472 is not allowed because it is not evenly divided by 32.
This might be a translation error. The map does not have to be 32 in both dimensions. Rather, it has to be a multiple of 32 in both dimensions.