I'm pretty sure I noticed a boost in Beta 3, but I didn't really dawdle that much during the Levequests so far. As the reward for time is rather minimal, I don't see why you wouldn't kill some other stuff anyway. ^^; As long as you know you can take down the actual Levequest targets with time to spare.
FFXIV, Trabia: Neasa Vera
FFXI, Leviathan: Aneirin (Dead), Key (Dead).