If you want to pull numbers, you should of went with Diablo 3 since it set records. But SALES are not SUBSCRIPTIONS. With MMOs specifically, they have a HIGH drop off rate after their first month, in fact only 20% of people who buy an MMO login after the first 30 days. That's a massive drop off, so to do your "10-20 mil SUBSCRIPTIONS" would require 50-100mil BOX SALES.
If you mean't box sales, then sure that's fine but you should correct your post.