The spar flange loads lessen as you go out on the spar that is why you can taper them. To make it easier to mill and set the rivets the spars are stepped on the 7. Therefore to sand off a small amount of material to eliminate the nicks still will leave much more material in the area shown than if the flange was an actual full taper instead of a step. I'm sure Van's will tell you the same.
N96FS, RV-6, 2WI6
Formally of Lafayette, IN