The problem with this is that you've nerfed the Mortar Pit's survivability (which isn't all that impressive) to make the Bofors easier to counter.
Not impressive but sufficient considering that a mortar pit is most of the time next to a Bofors.
The remove of the brace on it would allow to call artillery on it to destroy it. ( just one or two call-ins, and no 5054698436178e^9 like it's the case now )
So it would :
- Nerf the mortar pit in his globality. ( Nerf his survivability is a simple way to indirectly nerf all other stats ) And i think it needs this nerf.
- Allow to have better opportunities to kill the Mortar pit
so better opportunities to kill the Bofors, which is very strong with the Mortar pit, but fairly balanced without it. ( Mortar pit + Indirect barrage is actually a problem. The only way to counter these guys is sending Heavy Tanks or Tank Destroyers. But the brace could easily temporize for AT guns support. )
But of course, a reduction of the cost to balance all of that.
As i said it's not an "optimal theorycraft" suggestion( It's more a 10 sec brainstorm suggestion
), but i think we could give it a try.