So I took a little stroll down Murder lane to see how things went. Naturally didn't come very far but the little I've discovered is interesting.
Tests were conducted in a System ruled by an
Independent MF.
Went into a Weapons Fire detected (Threat 1) USS. Some Novice Viper Mk.4 and a Mostly Harmless wanted ship (don't remember the type).
Shooting at the Security ship granted me the initial 300 credits fine plus the timer being started (0m 40s).
Here's the amount of bounties I got on my head before they blew it away:
1st kill (Viper Mk.4): 7k
2nd kill (Anaconda): 42k
3rd kill (Eagle): 150k
4th kill (Eagle): 329k
Also the moment they had my shields down my FSD was immediately targeted and destroyed.
Mind you these were just regular Security troops coming into the instance. A more heavily engineered ship would've probably lasted way longer, but also accumulate a much bigger amount of bounties. Which in turn would mean the ATR ships would spawn faster.
So I went back (same System) and visited the local Nav Beacon. Things went like this:
1st kill (Hauler): 579k (Timer: 1m 30s started)
2nd kill (DBS): 901k
3rd kill (Anaconda): 1.3mil
4th kill (Cobra Mk.3): 1.8mil
5th kill (Viper Mk.4): 2.3mil
6th kill (Anaconda): 2.9mil (ATR Timer: 1m started)
So 10 ship kills gets you up to almost 10mil bounty which then will trigger the ATRs
on top of every other Security that'll be on your rear everywhere you go within the jurisdiction of the MF.
And every destroyed vessel after those will reduce the amount needed to trigger the ATRs until it's down to only 1 kill to make them say hello.