No arty in game fires only 4 shells.
ML-20 is supposed to fire 8 since always.
LEFH is supposed to fire 10 since always.
Add +1 at vet.
As clearly described in the patch notes ML-20 did not fire 8 shots "since always":
ML 20 152 Artillery
We want to encourage the use of the ML20 which was previously underperforming.
Salvos increased from 4 to 8
Removed precision strike at veterancy 1
Veterancy 1 now increases the number of salvos of the ML 20 by 2 (10 Total)
As clearly described in the patch notes LeFH did not fire 10 shots "since always":
LEFH 105 Artillery
We want to encourage the use of the ML20 which was previously underperforming.
Salvos increased from 6 to 10