Got it a month or so back, it's definitely not a fun one to do legit, that's for sure.
Especially for Breakthrough attackers, if you see a tank camping a little ways back, just plunk down some missile intercepts infront and watch the assists roll in.
A fantastic map is Black Field or whatever as the attacker with the armored transport -- situate yourself at the top of the hill where snipers like to gather and put missile and grenade intercepts down.
These work best with a partner who is an engineer - You can both get points/kills, there is always an option to repair, and having a driver means nobody can really do anything about you camping (and if someone on your teams tries to ram you it's easy to just move locaations. Lobbies with tons of bots work extremely well since they seem to prioritize vehicles with rockets.
It doesn't seem like grenade and missile intercepts work together, at least I haven't noticed them being cumulative - I'm fairly certain they each have their own counters