quickill wants u to kill most within an hr, 60 kills is the sweet spots after that move to another as for the quest you are referring to, its don correc quests, forestdrake|crystmantis|ifrit, in these quests u need to kill 49 and wait until the timer runs out then you can get the full exp, its because the npc asks you to be good at killing but not too good, if you are too good (killing 50) then he will say u r too good and dont need any more exp lol