I was bored waiting for weather to pop in the basement of Garlaige Citadel for a magian trial - so I just started killing at random.
I was a little shocked to see Chamber Beetles still checked easy prey at level 80. All of them did. I killed a handful, and got experience values of 23, 24 and 25.
I moved into the room with Hellmines and Skeletons, and discovered they still aggroed. Got experience values of 26, 28, 30 and 40. The one that yielded 26 experience also still aggroed.
Looked up mob levels, Chamber Beetles are 56-58, and Hellmines and Skeletons are 59-62.
It fit into a neat little package, so I killed a couple of Magic Jugs to fill out the experience values of EP/DC/EM at 80... level 59 was the aggro cutoff at 75, and it's STILL the aggro cutoff at 80.
I'm not sure if this is working as intended, but I'm sorely disappointed that Dire Bats and Robber Crabs will continue to aggro.
Lv. 55 = 00 XP (Too Weak)
Lv. 56 = 23 XP
Lv. 57 = 24 XP
Lv. 58 = 25 XP (This level and lower will not aggro under normal circumstances)
Lv. 59 = 26 XP (Monsters aggro 80s at this level - onward)
Lv. 60 = 28 XP
Lv. 61 = 30 XP
Lv. 62 = 40 XP
Lv. 63 = 50 XP
Lv. 64 = 53 XP