Simple, you give me 1 medium map, I give you 10 low maps.
Low maps in stock: 2000+ low maps.
Average 4 low maps to get 1 medium map.
That's an average of additional 6 low maps + dark signets + sards + leaves + crits for you to get me a medium map.
Your average profit:
6 additional low maps (which averaged to 0.5 medium map)
10 dark signets
4-15 sardonyx
7-18 leaf
2m - 8m crit
