Actually I punish any type of emplacement with a Mortar HT + 40 ammo, but that reduce my experience to 1 commander (I probably need to buy some other with the unit, probably Relic conspiracy to make me buy stuff)
After all if a Bofor is able to insta kill any infantry in range + light vehicles. It is fine to think any emplacement can be insta-kill by a mortar HT isn't it? same skill level is required.
He just brace for 30 sec, then what ?

Next patch you will have 60 sec to kill bofor after he brace ( maybe over nerfed, but its lelic )