Here is what has worked!! tried on multiple characters now Thanks @J0K3R and @Josh_K for providing the missing pieces
BaseArmorValue = ROUND(((CharaterLevel*7.5)*BaseArmor%))/(100-BaseArmor%),0)
%DefModArmorAdded = TRUNC((BaseArmorValue-ArmorAddedatCurrentGearLevel)*(%defMods/100))
ModdedArmorValue =
BaseArmorValue + %DefModArmorAdded + IntegerDefModArmorAdded
ModdedArmor% = ROUND((ModdedArmorValue*100)/(ModdedArmorValue+(CharaterLevel*7.5)),2)
Example 1
5's Base Armor 37.89%
Level 80
G10 with +15 armor added at G10
Mods with Defense
Diamond +8 and +11.75
Triangle +9
Cross +8
BaseArmor Value = Round(((80*7.5)*37.89)/(100-37.89),0)= 366
%DefModArmorAdded = TRUNC((366-15)*(11.75/100)) = 41
ModdedArmorValue = 366+41+8+9+8 = 432
ModdedArmor% = ROUND((432*100)/(432+(80*7.5)),2) = 41.86% Armor.
Shows same in game
Example 2
Kylo Ren Base armor 19.35
Level 70
G7 with 0 armor added at G10
Mods with Defense
Diamond with 11.75%
BaseArmor Value = Round(((70*7.5)*19.35)/(100-19.35),0)= 126
%DefModArmorAdded = TRUNC((126-0)*(11.75/100)) = 14
ModdedArmorValue = 126+14+0 = 140
ModdedArmor% = ROUND((140*100)/(140+(70*7.5)),2) = 21.05% Armor.
Shows Same in Game