Hi dude! you told me that in game as well, the only thing i can think of: some mobs dropp all of their items once you get to level 58, so something similar might happen with yang drop since you are 60 and i'm 54. Just a hypotesis tho
After today's update i'm gettin about 160-200k pure yang per metin with lucky gold coin IM only, so it would be like 80-100k per metin, the average would be a little bit higher since u can get an additional 40-45k yang if the mobs drop them on the ground (20-25k with 0% yang drop)