I think Sony had shipped about 5 million by the end of last year, if they upped their average this year to 1.3 million made a month, then they could ship another 15.6 million this full year from 1/1/2014 to 31/12/2014, so perhaps shipping 20.6 million by the end of this year is feasible.
IMO if PS4 has sold 12 million by the 4th of October, then 50% sales for the year this holiday would put it as 19.6 million by the end of the year.
I think 20 million may be a little bit too much, but I definitely think Sony can get close to it this year.
IMHO smashing 20 million by the middle of January is highly likely at this point, by the end of march next year I think 25 million will be easy for Sony to hit.
Sony will destroy their 17 million by march 2015 target very easily.
