Some time ago I have noticed strange property of the rocket launchers, based on tanks (RL T34 Calliope and RL M17 Whizbang) : they launch HE shells of the own 75mm and 105mm guns, during artillery phases, together with rockets!
As a result for example "Calliope" has 118 shells instead of 60 and rate of fire increases for 1/3.
Except for that , efficiency HE shells against light armored vehicles above than rockets.
Please correct this if it possible!