It's about time we figure out what this thing is doing. It doesn't appear to do ANYTHING versus too weak mobs, so I'm guessing it's somehow messing with pDIF somehow.
With this in mind, I collected some data. I went out and hit a bunch of LV100 Bluffalo in A-Uleguerand Range with regen atmas equipped.
Sylow
Melee
47: 10
48: 12
49: 21
50: 16
51: 11
52: 17
53: 26
54: 18
55: 11
56: 20
57: 17
58: 36
59: 19
60: 19
61: 14
62: 87
+ 63: 109
^ 64: 98
65: 104
66: 22
67: 14
68: 18
69: 14
70: 17
71: 19
72: 14
73: 16
74: 17
75: 18
76: 12
77: 16
78: 21
79: 17
80: 26
81: 15
82: 11
83: 11
84: 2
85: 3
86: 3
101: 2
102: 1
103: 1
105: 1
107: 1
108: 1
109: 1
110: 2
112: 2
113: 1
117: 1
118: 1
123: 1
124: 1
125: 1
127: 1
134: 2
136: 1
140: 1
141: 2
142: 1
143: 1
Melee Crits
100: 1
101: 1
102: 3
103: 6
104: 4
105: 6
106: 5
107: 6
108: 6
109: 7
110: 7
111: 7
112: 6
113: 5
114: 13
115: 11
116: 11
117: 11
118: 7
119: 5
120: 10
121: 11
122: 9
123: 8
124: 5
125: 9
126: 7
127: 10
128: 9
129: 6
130: 13
^ 131: 6
132: 7
133: 7
134: 11
135: 8
136: 8
137: 11
138: 8
139: 13
140: 8
141: 6
142: 4
143: 12
144: 13
145: 9
146: 9
+ 147: 15
148: 9
149: 14
150: 9
151: 10
152: 11
153: 2
155: 2
156: 2
173: 1
174: 2
175: 1
176: 1
177: 1
181: 1
187: 1
190: 2
192: 1
193: 1
Here's the non-crit in a pretty chart form:
Wearing this, no sambas up (although it shouldn't have mattered anyway)
I had absolutely no sources of double damage.
Looks sort of like it could have a ~3% rate of doubling your attack (or perhaps calculating as if your attack is capped, in this case, it's impossible to tell the difference between the two).
Edit: Please don't assume that IS what it's doing. I don't know yet. There are people who can probably look at this and figure out more what's going on more easily than I can. :)
Looks like it has a ~3% rate of doing something regarding pDIF equations.
It's not a direct damage multiplier, and it's not necessarily a direct boost to attack.