my guess would be that its checking your base conjuration attribute not your bonuses. conjuration levels very quickly though so just conjure some skeletons and cast turn undead on them for a couple minutes and you should be good. unless your enchanted items boostsed your conjuration a lot. then it might take alittle more time.
I think my base Conjuration is something around 90. I'm almost there anyways.
It was a test (I've never gotten into the Arcane University before, in 5 years and hundreds of hours of gameplay. Everytime I'd start to get deep with a character, I'd have computer issues and lose the character
), and I did beef up the spell pretty heavily. I just ended up making a slightly less powerful spell that still does what all I want it to anyways, and I'll just wait until I get it up there. Conjuration is one of my main skills on my character.