Are Nightblade Class Abilities Spells?

rlrch04b14_ESO

I really need to know about the Nightblade class skill lines. I am mainly Shadow/Siphoning and wanted to know if these abilities are considered to be spells? If they are indeed spells then my issue is the "Seducer" crafted set bonus to reduce cost of spells by 3% seems to be bugged and not working. I tested two abilities that use magicka and there was no change in the cost of using the abilities. Please explain/fix.

Samadhi

I'm also built heavily on Shadow/Siphoning right now.
I'm in Light Armour and my Robe is Robe of the Seducer.
1 piece of Light Armour (from passive) is 3%.
Seducer bonus is 3%.

Without my Robe of the Seducer on, my Swallow Soul skill is 247 magicka.
With my Robe on Swallow Soul is 230 magicka.
Mathematically, it should only be reduced to 233.

Dark Cloak and Twisting Path without the Robe on is 370.
With the Robe on it is is 345.
Mathematically, it should only be reduced to 348.

Seducer set is working fine for me; if anything I am receiving more reduction than intended.

rlrch04b14_ESO

Ah ok I discovered my problem. I did not realize the tooltip of the spell changed to include the bonus. Thanks