Fizzle rates affected by gear seems off

Reproduction rate : 100%
Blocker ? No
Details : Fizzle rate formula seems all over the place, I have been trying to work the numbers, and here is what I have. I haven't tested with all types of armor and stuff, pretty much Cloth / Bone and Wands / Staves / Shields.

Here is the fizzle rates off the gear I had my hands on for this test

Cloth Chest 0.0%
Cloth Legs 0.0%
Cloth Gloves 0.0%
Cloth Boots 0.0%
Bone Chest 12.0%
Bone Legs 3.0%
Bone Gloves 6.0%
Bone Boots 3.0%
Empty Hand/Off Hand -10.0%
Wand -15.0%
Shield 10.0%
Staff -30.0%

My Avatar has a level 80 Follow Through Skill giving me a base -10% Fizzle

Here is my Data, first things is gear I was using, then the 1st number is the standing still Fizzle Rate, and the 2nd number is the running fizzle rate. Running has a clean +29% Fizzle rate across the board but the gear combinations make the fizzle rate increase in wierd increments. I used the chain lightning spell as a tester but noticed the same changes in all the spells.

Full Cloth + Empty + Empty 0.00% 17.50%
Full Cloth + Wand + Empty 0.00% 0.00%
Why do I get a 17.5% difference between these 2 when only difference is a wand (-15%)
Full Cloth + Empty + Shield 3.00% 32.00*%
And here a 14.5% Increase compared to empty handed when shield is +10% and empty hands is -10%?
Full Cloth + Wand + Shield 0.00% 24.80*%
And now My -15% Wand gives me a 7.2% difference compared to shield and no wand, and a 24.8% compared to no shield?
Full Cloth + Staff 0.00% 0.00%

Cloth + Bone Chest + Empty + Empty 5.90% 34.90%
Now compare this with cloth chest, I should see a 12% increase, but running numbers show a 17.4% difference??
Cloth + Bone Chest + Wand + Empty 0.00% 13.20%
Cloth + Bone Chest + Empty + Shield 20.40% 49.40%
Cloth + Bone Chest + Wand + Shield 13.20% 42.20%
Cloth + Bone Chest + Staff 0.00% 0.00%

Cloth + Bone Chest & Legs + Empty + Empty 10.30% 39.30%
Cloth + Bone Chest & Legs + Wand + Empty 0.00% 17.50%
Cloth + Bone Chest & Legs + Empty + Shield 24.80% 53.80%
Cloth + Bone Chest & Legs + Wand + Shield 17.50% 46.50%
Cloth + Bone Chest & Legs + Staff 0.00% 0.00%

Cloth + Bone Chest & Legs & Gloves + Empty + Empty 19.00% 48.00%
Cloth + Bone Chest & Legs & Gloves + Wand + Empty 0.00% 26.20%
Cloth + Bone Chest & Legs & Gloves + Empty + Shield 33.50% 62.50%
Cloth + Bone Chest & Legs & Gloves + Wand + Shield 26.20% 55.20%
Cloth + Bone Chest & Legs & Gloves + Staff 0.00% 4.50%

Cloth + Bone Chest & Gloves & Boots + Empty + Empty 19.00% 48.00%
Cloth + Bone Chest & Gloves & Boots + Wand + Empty 0.00% 26.20%
Cloth + Bone Chest & Gloves & Boots + Empty + Shield 33.50% 62.50%
Cloth + Bone Chest & Gloves & Boots + Wand + Shield 26.20% 55.20%
Cloth + Bone Chest & Gloves & Boots + Staff 0.00% 4.50%

Cloth + Bone Chest & Legs & Boots + Empty + Empty 14.60% 43.60%
Cloth + Bone Chest & Legs & Boots + Wand + Empty 0.00% 21.90%
Cloth + Bone Chest & Legs & Boots + Empty + Shield 29.10% 58.10%
Cloth + Bone Chest & Legs & Boots + Wand + Shield 21.90% 50.90%
Cloth + Bone Chest & Legs & Boots + Staff 0.00% 0.10%

Full Bone + Cloth Helm + Empty + Empty 23.30% 52.30%
Full Bone + Cloth Helm + Wand + Empty 1.60% 30.60%
Full Bone + Cloth Helm + Empty + Shield 37.80% 66.80%
Full Bone + Cloth Helm + Wand + Shield 30.60% 59.60%
Full Bone + Cloth Helm + Staff 0.00% 8.80%

I left a couple notes in red, but didnt go through the whole thing, but the same issues show up the whole way down. I dont know how the math works behind the scenes for this, but it is clearly not what we are expecting...

5. Steps to reproduce : Equip different kinds of gear, look at fizzle rate for spells