Game Mechanics: Low level mobs double attacking

[Torven]

From examining AK logs, NPCs start double attacking at level 8 or maybe 7. I don't have long logs of this because I had only started collecting data after the shutdown notice, but I did produce some low level logs when collecting min/max hit data in 2013.

These are misty NPCs:

Fight #32 [16] A goblin warrior - Thu Oct 31 14:12:39 2013 - Duration: 58s (max hit was 18 indicating level 8)
Rounds: 20; Bashes: 8; Dmg Type(s): pierce; Swings: 23 (On You: 23)
rounds with 1 swings: 17 (85%)
rounds with 2 swings: 3 (15%)

Avg pre-slow round delay: 3.052; Rounds/sec: 0.327; Swings/sec: 0.396
Preslow Swings: 23; Preslow time: 58; Avg Swings/Round: 1.15
(1)3(1)3(1)3(1)3(1)3(1)3(2)3(1)3(1)3(1)3(2)3(1)3(1 )3(1)3(2)3(1)3(1)3(1)3(1)4(1)

Avg pre-slow bash delay: 8; Bashes per second: 0.125
8-8-8-8-8-8-8
-----------------------------------------------------------------------------
Fight #33 [17] A giant spider - Thu Oct 31 14:15:22 2013 - Duration: 1m 25s (max hit 16)
Rounds: 27; Bashes: 11; Dmg Type(s): bite; Swings: 27 (On You: 27)
rounds with 1 swings: 27 (100%)

Avg pre-slow round delay: 3.269; Rounds/sec: 0.305; Swings/sec: 0.317
Preslow Swings: 27; Preslow time: 85; Avg Swings/Round: 1
Adjusting for 1 outliers, 0 double rounds, and 0 post-cast rounds
Adjusted avg pre-slow round delay: 3.04; Adjusted rounds per second: 0.328
(1)3(1)3(1)3(1)3(1)3(1)3(1)3(1)3(1)3(1)3(1)3(1)3(1 )3(1)3(1)3(1)3(1)3(1)3(1)3(1)3(1)3(1)3(1)4(1)9(O1) 3(1)3(1)

Avg pre-slow bash delay: 8.7; Bashes per second: 0.114
8-8-8-8-8-8-8-8-15-8
-----------------------------------------------------------------------------
Fight #34 [17] A giant spider - Thu Oct 31 14:19:01 2013 - Duration: 49s (max hit 16 but only maxed once so level is uncertain; spawn chance is levels 7-9 for this NPC)
Rounds: 17; Bashes: 7; Dmg Type(s): bite; Swings: 18 (On You: 12)
rounds with 1 swings: 16 (94.1%)
rounds with 2 swings: 1 (5.8%)

Avg pre-slow round delay: 3.062; Rounds/sec: 0.326; Swings/sec: 0.367
Preslow Swings: 18; Preslow time: 49; Avg Swings/Round: 1.058
(1)3(1)3(1)3(1)4(1)3(1)3(1)3(1)3(1)3(1)3(1)3(1)3(1 )3(1)3(1)3(2)3(1)

Avg pre-slow bash delay: 8.166; Bashes per second: 0.122
8-8-8-8-9-8

All the NPCs that I'm sure are level 1-5 showed no signs of doubling. After level 8 I see doubling consistently.