Being able to change the AoA and bank in 0ne degree increments allows easier "tuning" of the reentry with AerobrakeMFD, and makes performing a fully unpowered reentry - landing on target easier.
Unfortunately, the DGIV will only increment in 5 degree intervals. Early in the reentry use the setting that leaves you "short", and lower the AoA later to extend the range as needed. It's easier to extend a reentry than to shorten one.