
How much flat spell cost reduction do you have? It looks like about -47 Magicka costs from your jewelry?
Then Expert Mage 10%, Breton 3%, Unholy Knowledge 5%?
You wear 5 pieces of Light Armour with 3/3 Evocation for another 15%?

It's not DR, it's just a function of the order they apply bonuses. In ESO they always apply flat additions/subtractions first followed by % increases/decreases.
Without your accessories your Bolt Escape would cost:
392 * 0.58 = 227
With them it costs
(392 - 46) * 0.58 = 346 *0.58 = 201