Board Thread:Questions and Answers/@comment-121.75.1.188-20141222182432/@comment-25854073-20141223215717

angel feather has a different upgrading ratio, its much higher, they noted that in previous patches...

for the rest of the treasures, 1-3 is 100%, 3-4 is NOT 90%... no friggen way i failed 5 times from 3-4...

from experience i think  3-6 is around 60%

and 6-8 is around 20-40%

and 8-9 is 5-10%