Thought here would be the best place for this. Wall of text inc!
QUOTE(Tenboro @ Feb 5 2012, 09:45)

Well, there is.
Lvl 300 MBP on Normal: qualityboost = 1094, quality_bonus = 0.30913798144906
Lvl 300 MBP on IWBTH: qualityboost = 1797, quality_bonus = 0.46689312369709
So on Normal it would be roughly equal to a Bunny-Girl Costume, while on IWBTH it would be somewhere between a Black T-Shirt and a Unicorn Horn.
Through extensive research into monster HP, MP, SP and base stats I have found the following.
Boss Base Stats vary
Legendary Base Stats 14,14,14,14,20,20
Konata Base Stats 16,16,16,16,20,20
Girls Base Stats 18,18,18,18,20,20
IPU Base Stats (haven't looked need scan data)
RL Base Stats 20,20,20,20,20,20
FSM Base Stats (haven't verified) 25,25,25,25,25,25
Mini-Boss HP Multiplier 1.5
Boss(MBP type) HP Multiplier 6
Konata HP Multiplier 16
Girls HP Multiplier 26
IPU HP Multiplier (need a scan)
RL HP Multiplier 51
FSM HP Multiplier (need a scan)
As we already know, monsters base stats are 1/10th of their level.
Also we know they get some bonus stats based on there level (formula unknown). @lvl 300 this is 152
MBP @ 300 Stats: 420,420,420,420,600,600
Bonus @300 Stat: 152,152,152,152,152,152
Total Stats @300: 572,572,572,572,752,752
Average Stats @ 300 = 632
Since at normal there is no multiplier, and also there are no other bonuses since it is just a MB, not in a grindfest, arena, ect all these bonuses can be zeroed, along with LotD, leaving us with just monster stats giving the bonus.
For Normal
632*sqrt(3)=1094.65, close to what Tenboro gave us, coincidence? Maybe, but without knowing more numbers its all we get.
For IWBTH
Initially tried
632*sqrt(8)=1787.57, close but off enough to keep trying
Next attempt
632*sqrt(6)+250=1798.07, close enough for now, espcially since the 152 level stat bonus maybe less then that and get rounded up to 152, if it 151.75 then this would be 1797.46.
This makes the difficulty bonus 250, and the monster stat bonus sqrt(2) for IWBTH
Therefore this stuff below
QUOTE
From Wiki
Loot Factors
Difficulty Bonuses
Easy = x0.5 Difficulty Factor.[3]
Normal = x1 Difficulty Factor; x1 Monster Stat Bonus.
Slow, unknown increase of bonuses up to Battletoads.
Battletoads = x2 Difficulty Factor; x4 Monster Stat Bonus; +500 Difficulty Bonus.[4]
IWBTH = Unknown.
Battle Mode
Hourly Encounter: A static Round Bonus is set at +250.
Grindfest / Item World: A variable Round Bonus starts low and increases with each round played, maxing out at +500 at round 100.[5]
Arena: A static Arena Bonus is given based on the arena level. No bonus during First Blood, +100 during Graduation, and then adding about +50 for each level afterwards.[6]
Formula
Note that in addition to the possibility that this formula is outdated, the specifics in calculation of various base bonuses are not known to the public.
The estimated end formula is:[7][8]
Loot_quality = Initial_quality_roll(1-1000) + (Difficulty_bonus + Round_bonus + Monster_stat_bonus + Arena_bonus) * Difficulty_factor * (1 + Luck_of_the_Draw_level * 0.01)
is outdated, which isn't surprising considering most of the data we got is from over a year ago. Also the Difficulty factor seems to be not used anymore, or does not multiply Monster_stat_bonus, or Difficulty_Bonus, because if IWBTH has higher quality then Battletoads, it should be more then twice as much as Normal, and if it was used along with the difficulty bonus and multiplied it IWBTH MBP should be at least have 1000 more qualityboost
Proposed new formula:
Loot_quality = Initial_quality_roll(1-1000) + (Difficulty_bonus + Monster_stat_bonus*Difficulty_Multiplier + ((Round_bonus + Arena_bonus) * Difficulty_factor)) * (1 + Luck_of_the_Draw_level * 0.01)
Where
Battle Mode
Hourly Encounter: A static Round Bonus is set at +250.
Grindfest / Item World: A variable Round Bonus starts low and increases with each round played, maxing out at +500 at round 100.[5]
Arena: A static Arena Bonus is given based on the arena level. No bonus during First Blood, +100 during Graduation, and then adding about +50 for each level afterwards.[6]
(unchanged since I have no data to prove otherwise)
Loot Factors
Difficulty Bonuses
Easy = ?
Normal = x1 Difficulty Factor; x1 Monster Stat Bonus.
Slow, unknown increase of bonuses up to IWBTH.
IWBTH = Unknown Difficulty Factor, sqrt(2)x Monster Stat Bonus, +250 Difficulty Bonus
Disclaimer: Two points of data are not enough to get anything conclusive. These numbers have been forced to fit the end values with what I have been given or been able to determine. There may be more factors that belong in the equations that I ignored due to insufficient data. Until proven or Tenboro verifies I suggest we leave the wiki page unchanged, just increase the size of the disclaimer stating its outdated.