No difference, just a matter of preference and what you are going for. I've seen recipes using anywhere from 4oz to 1.5 lbs in a 5 gallon batch. I would stick with what your recipe calls for and then you'll have a baseline from which you can make some decisions if you brew it again.
Draft 1: Lightly smoked Weizen
Draft 2: Belgian Wit
Draft 3: Rauchbier
Primary 1: German Scwarzbier
On Deck: Belgian Brown Ale, Pale Ale, Stout