Modify Wall Assembly

[cadman6735]

I am playing around with the (Modify Vertical Structure) under wall properties Assembly view.

I have sort of figured out the split region 'horizontaly' but split region Verticaly what purpose would this serve me?

in the example file I attached I am asking about the 1" & 4-1/2" measurements. What purpose does splitting the region verticaly do for me?

What other neat tricks can I pull off in this assembly modify section?



Thanks