User blog comment:Andre5913/Fully Pokemon-ized Champions/@comment-4636093-20140503104753/@comment-4636093-20140504193852

^Those aren't official stat boosts. Think of it this way; Rammus increases his Armor and MR when he uses his W, Alistar gains % damage reduction when he ults.

While it accomplishes the same thing, it stacks differently.

But then adding one of those moves will then double it again. Reflect on its own is worth 2 stat boosts, Reflect + a Defence Curl is worth 4.
 * +1 = 150%
 * +2 = 200%
 * +3 = 250%
 * +4 = 300%
 * +5 = 350%
 * +6 = 400%