[quote=Dynamics]
Not really. If it's slowed down for her, it takes twice as long to actually activate it and cast it.
[/quote]

Let's look at it this way. There are two different scenarios for this: 1. Her brain operates at the same speed in her perspective, thus allowing her to do more things in the slowed time flow, or 2. Her brain operates slower in proportion to how the time is slowed.

If time is slowed down by two (1 second in normal is two in slowed): If 1) is true, she'll be able to do twice as many things in the slowed down time as in the outside time. If 2) is true, her brain will be moving half as fast as normal, taking her two seconds in the slow time. Basically: 2 seconds in slow time occur in 1 second in normal time. If it takes her 1 second at normal brain speed, and her brain is moving half as fast, it takes her two seconds in slow time.