Firstly the control test;
Non-VIP, No Gum
Test Test 1 Test 2 Test 3 Total Item/Mushroom Drop Table ±% Drop Table
Shrooms Killed 250 250 250 750 - - -
Mushroom Spore 254 274 263 791 1.0547 1.1000 95.88%
Poison Spore 132 126 144 402 0.5360 0.5500 97.45%
Feather 44 48 50 142 0.1893 0.2000 94.65%
Elemental Stone 14 23 16 53 0.0707 0.0900 78.56%
Alcohol 2 0 2 4 0.0053 0.0050 106.00%
Mixing Reagent 0 2 1 3 0.0040 0.0050 80.00%
Dew Laden Moss 0 0 0 0 0.0000 0.0020 0.00%
Before I could work out how VIP and Gums interact, I'd need to know how they work individually in the first place. So I tested whether Gums really worked on re-rolls or not.
Non-VIP, HE Gum
Expected Results
Re-Roll Theory 90% Cap Theory
in 250 in 750 Item/Mushroom in 250 in 750 Item/Mushroom
Mushroom Spore 454 1363 1.8178 450 1350 1.8000
Poison Spore 227 682 0.9089 225 675 0.9000
Feather 122 366 0.4880 150 450 0.6000
Elemental Stone 62 185 0.2464 68 203 0.2700
Alcohol 4 11 0.0149 4 11 0.0150
Mixing Reagent 4 11 0.0149 4 11 0.0150
Dew Laden Moss 1 4 0.0060 2 5 0.0060
Results:
Results Test 1 Test 2 Test 3 Total Item/Mushroom ±% Re-Roll ±% 90%
Shrooms Killed 250 250 250 750 - - -
Mushroom Spore 444 448 460 1352 1.8027 99.17% 100.15%
Poison Spore 218 213 223 664 0.8853 97.40% 98.37%
Feather 153 160 151 456 0.6080 124.59% 101.33%
Elemental Stone 60 73 73 206 0.2747 111.49% 101.74%
Alcohol 3 4 3 10 0.0133 89.26% 88.67%
Mixing Reagent 2 1 2 5 0.0067 44.97% 44.67%
Dew Laden Moss 0 0 2 2 0.0027 45.00% 45.00%
From the above data, the results from matched the 90% capped multiplication theory more so than the re-roll theory.
So now, a test on how VIP works.
VIP, No Gum
Expected Results:
Re-Roll Theory 90% Cap Theory
in 250 in 750 Item/Mushroom in 250 in 750 Item/Mushroom
Mushroom Spore 337 1011 1.3475 413 1238 1.6500
Poison Spore 168 505 0.6738 206 619 0.8250
Feather 70 210 0.2800 75 225 0.3000
Elemental Stone 33 98 0.1310 34 101 0.1350
Alcohol 2 6 0.0075 2 6 0.0075
Mixing Reagent 2 6 0.0075 2 6 0.0075
Dew Laden Moss 1 2 0.0030 1 2 0.0030
Results:
Results Test 1 Test 2 Test 3 Total Item/Mushroom ±% Re-Roll ±% 90%
Shrooms Killed 250 250 250 750 - - -
Mushroom Spore 411 405 408 1224 1.6320 121.11% 98.91%
Poison Spore 200 199 204 603 0.8040 119.32% 97.45%
Feather 66 75 77 218 0.2907 103.82% 96.90%
Elemental Stone 28 30 30 88 0.1173 89.54% 86.89%
Alcohol 2 3 1 6 0.0080 106.67% 106.67%
Mixing Reagent 4 0 3 7 0.0093 124.00% 124.00%
Dew Laden Moss 1 0 2 3 0.0040 133.33% 133.33%
Once again the results closely matched 90% capped multiplaction as opposed to re-rolls.
Now the test to see how they work together.
VIP, HE Gum
Results Total Item/Mushroom ±% Drop Table
Shrooms Killed 1000 -
Mushroom Spore 1792 1.7920 162.91%
Poison Spore 897 0.8970 163.09%
Feather 697 0.6970 348.50%
Elemental Stone 298 0.2980 331.11%
Alcohol 19 0.0190 380.00%
Mixing Reagent 7 0.0070 140.00%
Dew Laden Moss 5 0.0050 250.00%
As you can see, the Mushroom Spores and Poison Spores have a much lower percentage change from the drop table than Feather and Alcohol. This clearly demonstrates that the 90% cap exists and is affecting the drops.
Now, looking at the Feathers, the drops have increased nearly 350%. Now it seem very much like a stab in the dark to say that VIP works like Gum bonus and the bonuses are added togther to form +250% (for HE Gums). However, when VIP was launched, this is exactly what happened to VIP and Battle Manuals. No one picked it up for Gums because most people, Community Moderator Heimdallr included, believed that Gums worked on the re-roll theory.
Because it seemed like a stab in the dark, I decided to test this further, see below.