With the introduction of the new call in atillery DF added penetrating fragmentation with 45mm of pen to them to improve the effectiveness agains tanks while he same rocket fired by a vehicle only has 9mm of pen on direct hit (Do not question DF logic).
This feature would be amazing for larger caliber HE of the 100+ mm or larger HE slinger as in their current implementation they are unable of abuseing the thin roof of a lot a tanks.
For example:
The 120mm Chi Ha short gun with its 31 mm of pen cant kill a Grant by shooting the spot where the turret and the tank roof meets even though the roof ,directly underneath impact, is only 12.7 mm thick.
The penetrating fragmentation would be able to travel through the air around the impact and make use of such weakspots that the main explosive cant reach due to how horrible the engine treats those.