CryptoLocker: 250K infections in 100 days nets $300,000 or does it?

According to Dell SecureWorks Counter Threat Unit (CTU) security researcher Keith Jarvis, the CryptoLocker ransomware that has been written about so much of late has infected as many as 250,000 computers during the first 100 days of distribution (staring on the 5th of September, 2013). What's more, Jarvis estimates, based upon independent research, that owners of at least 0.4% of the infected machines will have paid the ransom demanded in order to unlock their data. Some pretty simple maths says that the $300 ransom multiplied by 1000 users equals a net haul of $300,000. Right? Well, maybe not.