I don't know how "new" this method is since it is the way we were instructed to use the A2 when we transitioned from the A1 back in '85 or so.
By setting the rear sight to 8/3 -2 and adjusting elevation on the front sight post to obtain POA=POI with the small rear sight aperature at 200yds/m, the rifleman will be able to then set the rear sight to 8/3 +/-1 to obtain a POA=POI at 300yds/m, at 400yds/m 4 +/-1, at 500yds/m 5 +/-1, so forth and so on out to 800yds/m.
Also, with the rear sight set to 8/3 -2 and using the large 0-200 aperature, the rifleman has a very flat 0-200yds/m zero that is fast and easier to aquire in a high stress close range encounter.
Remember, the USMC KD range is very similar to a service rifle match, but the targets are a bit different and the scoring was changed, about '96 if memory serves, to a hit/miss type of affair, after all, in combat only hits count. Whereas Match shooters require a higher/finer degree of sight manipulation, hence the 1/4 and 1/2 MOA clicks found on Match rifles.