Going forward we can look into these rates, however, related to Treasure Maps the platinum was meant as a nice reward combined with the rest of the loot. In the last patch we increased the amount of platinum in a level 6 chest from 1 coin, to 3 coins. Combined with the increase in loot, high chances for masks, and additional gold level 6 maps should provide a much more adequate reward for a small party. AS they are our "boss" item for treasure hunters, we might look at some other changes in the future. Note: Level 6 maps originated as a placeholder for loot on the boss monsters. With the platinum system and completed loot system for bosses, we have scaled them back to a 10% chance. The primary method for gathering platinum will always be the champion system.