Hmm my formula's very off then, that or the "Troop:Pop" ratio factor wasn't reverted and as the target's troops reached 0, he took more damage (was this the same thing as the reverted ramping up factor?).

If I change it so that I assume GSes kill 4% pop instead, AND round up/down every turn's pop killed (I hadn't done any pop rounding in previous cases), I get the following with 0.7% DR per hit:

For a 260k pop country (GS - 4% per hit rounded up every hit):
290 hits (4.83 min at 60 hits/min)
388 hits (2.98 min at 130 hits/min)
601 hits (<1 min)

For a 260k pop country (GS - 4% per hit rounded down every hit):
290 hits (4.83 min at 60 hits/min)
388 hits (2.98 min at 130 hits/min)
626 hits (<1 min)

So rounding up/down only affected the number of hits in the very fast kill.

Does this new estimate better match what is expected for a slower kill? Under the OLD formula with no DR and no ramping up last year, still assuming 4% per hit rounded down, the same 260k pop country would have take 215 turns to kill.

The numbers will be a bit off since I didn't take any NW difference between the attacker/defender isn't taken into account.

This looks reasonably better since the number of hits needed isn't all that excessive unless you wanted to kill in less than a minute, but I think qzjul will need to script a test up to have a country attack exactly once per second on the alpha servers to simulate the "60 hits/min" scenario.