Blessed Aura on hero

I'm trying to use this enchantment & it doesn't seem to work. The hero casts Aegis which lasts 11 secs with 15 in PP. Shouldn't the spell last for 14 to 15?
I'm looking at the spell in the upper left corner of the screen after it's cast.
Edit : Thank you

The number doesn't change in the skill icon, it will just last longer. That is probably because some enchantments have fixed durations and you can't change that. Old healing breeze just for an easy number, the skill description said 10 seconds, and even with a 20% enchant mod it would still say 10 seconds in the description, but it would last for 12.

The only time the skill description changes is when your attributes change. Awaken the Blood, Glyph of Elemental Power, etc. will make skill descriptions change, as would consumables like Grail of Might.