Test Sandra Skill "Find Treasure" double chance drops,
( and using Skill "Robbery" under fight )
10 battle of low level mobs without the Skill,
10 battle of low level mobs with Skill active.
Résults: dont work with Robbery
Skill Inactive: Total gains = 56 items and 690 K. gold
Skill Active: Total gains = 41 Items and 880 K. gold
I think Robbery Drops are not affected from Skill "Find Treasure".
Seems to be the inverse with the Items.