Mortars get +1 ROF. Intentional?

[Case23]

I noticed that Soviet mortars get +1 ROF when firing indirect (haven't tested other nationalities). Off-board arty does not get this (again at least for Soviet units). Haven't tested other on-board arty.

Is this intentional? (I neither criticize nor praise, merely seek enlightment.)

- Case23

[DRG]

It works exactly the same for all nations in both games and it's been that way for years

Don