I pm'd you but figured I'd post here also for others. The enchant became 15% when disenchanting the 40% item as only the base enchantment is added to your enchanting list, not the specific enchantment that was on the item. For 'Resist Frost' the enchantments are; Base (15%) - EnchArmorResistFrostBase "Resist Frost" [ENCH:0010FB8C] of Resist Frost (15%) - EnchArmorResistFrost01 "Resist Frost" [ENCH:0004950C] of Waning Frost (30%) - EnchArmorResistFrost02 "Resist Frost" [ENCH:000AD485] of Dwindling Frost (40%) - EnchArmorResistFrost03 "Resist Frost" [ENCH:000AD486] of Frost Suppression (50%) - EnchArmorResistFrost04 "Resist Frost" [ENCH:000BE02B] of Frost Abatement (60%) - EnchArmorResistFrost05 "Resist Frost" [ENCH:000BE02C] of Warmth (70%) - EnchArmorResistFrost06 "Resist Frost" [ENCH:000BE02D] As for the math, need to know all the enchanting perks you have, Enchanting skill and Soul Gem used. This is the formula used; Apparel (all non weapons): net magnitude =
base magnitude * soul multiplier * skill multiplier * (1 + perk) * (1 + specific perk modifier)"Base magnitude" is the %value of the enchantment as a whole number, 15% = 15. "Perk" is the value of the bonus as a decimal, +75% = .75. Repeat the "* (1 + perk)" portion for each enchanting perk that increases enchanting strength. Ranked perks (Enchanter 1/5, Enchanter 2/5) will normally cancel previous ranks, but some mods may make them additive.* Perks that reduce the effectiveness of an enchantment (Extra Effect) are added to the end of the formula as "* (0 + perk)" so a 20% weaker perk would be "* (0.8)" "Specific perk modifier" is stuff like defender (SkyRe), in vanilla it is Fire Enchanter, Frost Enchanter, Storm Enchanter, Insightful Enchanter and Corpus Enchanter, since only 1 of those will apply to any one enchantment at a time. soul multiplier = Class Multiplier Grand x1 Greater x2/3 Common x1/3 Lesser x1/6 Petty x1/12 skill multiplier = approximately
1 + (skill/100) * (skill/100 - 0.14) / 3.4*Additive ranks: rank 1 is +10%, rank 2 is +10% but says it's +20% as it adds its 10% to rank 1s 10%. Additive perks in a multiplicative formula do not equal the sum of the parts, they equal more. 10% (r1) + 10% (r2) = 21%, 50% (r1) + 50% (r2) = 125%. The vanilla enchanting perks are not additive like this, Enchanter rank 2 disables the bonus from rank 1 and replaces it with the higher bonus, rank 3 disables rank 1 and 2, etc.