Per ESPN's article on changes under the new CBA:
After the 2012 season, about five to six additional major leaguers will become eligible for salary arbitration each year. The group of players with at least two but less than three years of major league service lost the right to arbitration in the 1985 agreement, but players regained it for the top 17 percent of 2-3-year players by service time in the 1990 deal. That will rise to 22 percent following the 2012 season.
So under the new CBA, Super Two status not only remains, but expands. Under the old rules, the cutoff was usually between 2 years, 128 days and 140 days, with the historical range 122 days to 147 days. Hosmer appears to have earned 147 days of service time this year, so under the old system he was likely to qualify for Super Two status. With Super Two cutoff lowering under the new CBA, Hosmer is virtually guaranteed to be a Super Two unless he gets demoted to the minors between now and the end of the 2013 season.
Super Two status does not affect how the long the Royals have Hosmer under team control, but it means that he will qualify for arbitration four times instead of three, thereby costing the Royals millions in future salary.