When we originally designed and implemented the bonus values for monster damage in Inferno, we were unaware that a bug was causing monster abilities (i.e. Rare and Champion affixes) to not scale correctly with each Monster Power level. While this bug was caught during testing and did not make it into the game, the result of it being fixed meant that monster damage -- specifically damage done by monster abilities -- was ultimately higher at MP1 through MP10 than we intended it to be when 1.0.5 released.
So, to bring monster damage back in line with our original goals for the system, we're implementing a hotfix that will reduce the scaling bonus to monster damage in Inferno difficulty by approximately 25% for all Monster Power levels.
Here are the new damage values that will be hotfixed in for each MP setting:
MP1: 109.60% (down from 114%)
MP2: 120.12% (down from 130%)
MP3: 131.65% (down from 148%)
MP4: 144.29% (down from 169%)
MP5: 158.14% (down from 193%)
MP6: 173.32% (down from 220%)
MP7: 189.96% (down from 250%)
MP8: 208.20% (down from 285%)
MP9: 228.18% (down from 325%)
MP10: 250.09% (down from 371%)
Please note that these changes will only apply to monster damage in Inferno difficulty. Monsters in Normal, Nightmare, and Hell will be unaffected and continue to use their current values.
This hotfix is currently scheduled to be released tomorrow morning during normal Tuesday maintenance in the Americas, which means the new bonus damage values in Inferno will take affect once the game servers come back online.