medium adventure search

When checking through some various sites i discovered that the medium treasure was supposed to yield about a 66% chance of finding an adventure. However since starting the search i am 0 for 12 in searches... I think the developers either need to give an accurate depiction of what the real percentage is or fix the problem an make it closer to the percentage stated. I dont see the point in spending 30 coin for each search now waiting for 13 and 14 in the hopes of finding an adventure thats most likely going to be worth 1/4 what i spent to find it.