Back when Air Transport aircraft carried navigators para Drop Zones were laid out with markers to aid recognition of the CARP or calculated air release point. On special DZs a simplified identifier was placed at the release point on the ground which was calculated by the army. There were no impact point markers. Therefore any drop error was the responsibility of the DZ party. Often thereafter the marker was put on the IP and navs were asked to CARP onto that. When GPS/IN kit arrived it could calculate a release point but was always verified by the nav.
Now that navs are replaced by a reading on a HUD in front of the pilot you get what the computer says is correct. One consolation point is that the paras never miss the ground.