I like to know where my stats are coming from. I think its confusing that the protection spells always report their base armor even when the Vanilla Mage Armor perks multiply this value two to three times. The total armor is reported when viewing your inventory, but this doesn't match up with what is shown under active effects. After I spent a few minutes with the creation kit it became clear why this is the case: consistently providing the correct amount of armor, and displaying the correct amount in the active effects, is more complicated than it seems. But I eventually found a solution that I feel works well at conveying where your armor is coming from, and this mod is the result.

What it does:

The Mage Armor Perk passively gives 33/66/100 Armor rating when no armor is worn, displayed under active effects. This change was inspired by the Better Magic mod by sushisquid. This helps to keep the Mage Armor perks relevant even after obtaining Dragonhide by providing some defense when not actively using a protection spell. For consistency, the Mage Armor effect is temporarily dispelled when Dragonhide is cast.

The armor from protection spells is still multiplied by the perk, but now the extra armor is added directly to the new Mage Armor passive and the active effect is updated to show the actual amount of armor gained. For example, when casting Ebonyflesh with 2 points in Mage Armor, the Mage Armor active effect will show 216 armor (1.5 X 100 + 66), while the Ebonyflesh active effect will still display its 100 Armor as in vanilla, for a total of 2.5 X 100 + 66 additional armor.

Note that NPC's with the Mage Armor perks will receive the same amount of bonus armor as the player when casting a protection spell.

While developing this mod I noticed that Dragonhide does not work correctly when any protection spell is active. Although it consumes its mana cost and a casting effect is shown, the active effect does not show up and the 80% damage reduction does not seem to work. Similarly, if you first cast Dragonhide and then cast any protection spell, the spell seems to dispel Dragonhide. This bug is present in an unmodded Skyrim, and does not seem to be fixed by the USKP. It appears to occur because the magic effect associated with Dragonhide uses the Peak Value Modifier Effect Archetype with the same keywords as the protection spells. However, since Dragonhide has no magnitude, the other spells win out and it is instantly dispelled. As a bug fix, I've altered Dragonhide to use the Value Modifier Effect Archetype and added conditions to the normal protection spells so that they temporarily dispel whenever Dragonhide is active. The same changes were made with regards to the Bones of the Earth power as it essentially works the same as Dragonhide and had the same problems.

Compatibility:

Two versions exist: one Vanilla Skyrim, and another for Dragonborn.

This mod should be compatible with any mod that does not change the Mage Armor perks or the protection spells. If another mod adds new protection spells, any bonus armor they get from the Mage Armor perks will not show up in the Mage Armor active effect.