Some quick (and probably not 100% accurate) math tells me that if you bottled 50 bottles and used 5 oz of priming sugar, you'll get approximately .29 of a point (.00029) extra gravity in each bottle. So, in a nutshell, it affects ABV, but not on any noticeable scale.
Carbing is achieved by containing the byproducts of fermentation. So, if you add too much sugar, it will continue to ferment in the bottle, exceed the pressure capacity of the bottle, and cause bottle bombs.