That sounds about right to me. I came across one in my INV that had that amount and I know I didn't make it - "Peerlless" in the name maybe?
Peeless, there's a typo in game, or Peerless as it appears in the CK/wikia items list is 25%, according to the CK a Ring of Resurgence is found in 2 "users" (QAEnchantedArmorConatiner and LItemEnchMagickaRate) and uses the highest MR EnchantArmorFortifyMagickaRate05 (not player created); which according to the enchant description is 80%
150%. Didn't dig further for where and when the leveled items are in game nor the container.
Cheers,
Bram
P.S. Reverified I'd clicked on the one below in the CK for robes, DOH!