It's not a bug. Think about it: part of the skill requirement in this combat system is your ability to make quick decisions and fluid changes in battle, whether it's early activation, canceling out, or the optima-change/paradigm-shift cancel trick. By setting battle speed to slow, you're effectively lowering the game's difficulty, as such, your rewards are diminished.
I think it makes perfect, logical sense, actually.
PS3 Running 24/7 since: 30 JAN 2008
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