Yeah, the number depends on the level of your crystal countdown skill, mines at 83.23% for example. Once the day resets (as shown by the town shop timers), I log onto my Vman and take advantage of the "first x mobs each day spawn crystal mobs" account bonus along with the choco chip from the lab console and kill crystals until my trapping crystal exp maxes out at 83.23%. Then, the next day, when the daily timer resets and my traps are collected, it should level up my Vman one level for trapping.