I like the duo of one OP Mage spec’d for power, and the other spec’d for precision. But it’s a weird choice to make both of them lack common sense. It’s like the blind leading the blind.
Seriously though, in this case the MC’s problem isn’t common sense, it’s reading comprehension. Because the description of her ability clearly spelled out what it is she does. Yet, for some reason, his brain is unable to process it.