Brown Sugar and Hops

[HeritageHD]

Im going to brew the breakfast stout kit from Jaspers and wanted to know why the hop schedule changes between the two recipes they offer - the I Eat Danger and the I eat Danger in Kentucky.

The only difference in the two is the addition of brown sugar and bourbon and changing the hop schedule as follows:

Without Brown Sugar:
2 oz Horizon Hops (Bittering, 65 minutes)
½ oz Willamette Hops (Bittering, 30 Minutes)
½ oz Willamette Hops (Aroma, 1 Minute)

With Brown Sugar:
1 oz Horizon Hops (Bittering, 65 minutes)
1 oz Perle Hops (Bittering, 65 minutes)
1 oz Target Hops (Bittering, 65 minutes)
½ oz Willamette Hops (Bittering, 30 Minutes)
½ oz Willamette Hops (Aroma, 1 Minute

Is the purpose just to balance the flavors of bourbon and brown sugar? How much would the addition of those two ingredients change the flavor profile?

Thanks!