I would like to share something:
What make the MLRS a nightmare to deal with in WWII is the firepower concentration, abate only for one salvo. If a MLRS with 12 launchers a system is as expensive as a howitzer, the missiles have explosive force as a round, the first salvo of a MLRS is 12 times that of a howitzer. That concentration of firepower is overwhelming to an opponent. Let's call that the alpha strike (I know the USN's alpha strike, just borrow it here for simplicity's sake)
combined this with smoke mortars and creeping barrage, timed the alpha strike just when the stormtroopers about to get to the enemy's line and voila, the line crumble asap
).
Just my 2 cents.