LAS allows shooting from decreased slant range which is essential for sufficient penetration on a hard target.
HAS requires greater slant ranges because you need time and distance to complete the dive recovery.
Does the thinner armor on top of tanks negate the reduced bullet penetration capability? It depends (tm).
Target type, aspect, dive angle, slant range, and rounds fired all affect the answer.
Also, a two second burst is used in most tactical situations against a point target; a specific round count isn't really planned. In training, the goal is 100 rounds per event for scoring purposes.