To exclude the impact of xeh and weapon weaks for test purposes, the non-repl-config includes an implementation without xeh and BI-standard weapon layout (in this case the Brad is equipped with a 2A42). You can check this, when you remove the xxx_repl.pbo.
Well, the reluctance is caused by the ffMagnitude and maxRange values, I think. When I lower the maxRange value to 500, all ground vehicles with distance >500 are attacked by TOW. To my surprise, tanks are always attacked by TOW, so I think you are right, when it comes to high armor values. But the BMP is somewhere in between.
I have not tweaked the TOW, because I guess that others may already have tweaked it
I am using another "tweak" on my own, because the BI-TOW has a maxLeadSpeed = 10... each faster vehicle cannot be aimed, while the AT5 has a maxLeadSpeed = 100
We have discovered that some vehicles behave different from SP / MP. I guess a dedicated server has more priority on AI behavior, while the graphics display seems to have an impact on this. Especially in waypoint behavior, we noticed a big difference between SP and MP.