Seems pretty reasonable overall.
Source: http://www.vg247.com/2013/05/30/take-two-ceo-talks-gta-5-used-games-unprofitable-mmos/VG247 said:He also said he expects Grand Theft Auto 5 to sell 18 million units in its first year. Zelnick said pre-orders for the title are doing very, very, very, very, very, very well. Grand Theft Auto 4 has sold 25 million units to-date, and the current install base is three times what it was when that game launched
Zelnick is of the belief that A games like GTA are what sell, not B games, and customers only want to purchase the best intellectual property out there. One such title was Red Dead Redemption, a game with immensely profitable expansion packs.
The one which sold the most, however, was Undead Nightmare and its zombified cowpokes and wildlife.
We had the presence of mind to add zombies to the title; and everyone always loves zombies, Zelnick said. Id like to do zombies in everything, but I probably cant say that here. But they do sell.