Reduce Spell Cost glyph: wrong amount of magika reduced

PlumpOrange

Hello, I have the Breton templar healer and I wanted to run some Reduce spell cost glyphs on my jewelry. A crafted truly superb gold glyph claims to reduce the cost of any spell by 201 magika, but in fact, if you look at your skill costs in skill meny before and after the glyph slotted, with simple calculations you will find that it reduces only 169 magika.

Is it a bug or feature some kind of interaction with the Breton reduce spell cost passive?

paulsimonps

In the formula for calculating the cost Enchantments goes first and the breton passive after. Aka the 200 the glyph reduces the cost with is the base cost of the skill, not the 3% less Bretons have, the 3% is removed after the glyph has removed 200 from the base cost. That is why it seems like it does less to you.

PlumpOrange

But the glyph reduced only ~160, not 200

paulsimonps

Below is shown an example. We have a skill that costs 4000 in its base form. You add a spell cost reduction glyph and the breton passive. This is how it is calculated.

(4000-200)*0.97=3686

What you are seeing is this, the ability cost without the spell cost reduction glyph.

4000*0.97=3880

The difference between the two is:

3880-3686=194

This does not mean that the enchantment is bugged cause if you do this without the breton passive instead we get

4000-200=3800

And we can clearly see that the glyph does indeed decrease the cost by 200. Its just that the glyph is calculated before the passive so what you think is the base cost is really not the base cost and you are missing a side of the equation.