The LeFH has little over half the damage of the ML-20 while only firing slightly more shells and having the same exact accuracy and cost. Comparing the two is really dumb because the LeFH does less AoE damage while shooting at larger squads while the ML-20 has much higher AoE while shooting at much smaller squads.
LeFH cooldown starts with the first shell, ML-20 with the last, which means LeFH has much shorter cooldown and your saturation is much greater.
Checking only damage and shell number gives extremely misleading performance view.